While the US landing at Guadalcanal in August of 1942 was relatively unopposed, later landings were not. Furthermore, the beaches in the Pacific were almost completely uncharted and hard to access, a big difference from the European theatre with its short distances and well-charted shores. Some effort was made to chart shores with aerial photography but these efforts were largly unsuccessful. NCDU's were considered for use in the large landings but were thought to be too small, there was more than just blowing known obstacles to do. Therefore a rushed program was started to create larger units, utilizing core members of several NCDU's but augmenting them with Navy Seabees, Marines, and Army Combat Engineers to get the larger teams. Not only would they demolish obstacles, they would first find them and also map the landing zones and conditions. These teams were christened Underwater Demolitions Teams One and Two, and were still in training when the US launched Operation Galvanic, the invasions of Tarawa and Makin atoll.

Taking place in November of 1943, the US Marines assaulted Tarawa and Makin in the Pacific. Although both islands were taken, the landing at Tarawa was a disaster and Makin nearly so. Relying on old maps and ignoring intel about intense currents that appeared during the planned invasion window, the Navy's plan at Tarawa left the Marines half a mile out from shore. Fully loaded Marines were forced to wade across the open coral reefs to shore under intense fire. In addition to deaths from enemy fire, many Marines were killed when the weight of their gear pulled them under when they stepped into holes caused by bombs and mortar shells. Makin's beach proved to be so small that there was a severe bottleneck of landing craft and it was only the total lack of defense on the beach that allowed the US to take the island without a bloody assault.

Operation Galvanic taught the Navy some serious lessons. Photo recon and old maps were not enough to plan a large invasion of hostile shores. They would need men on sight to chart the beaches and their approaches. Despite popular notions that the need for UDT's came from Tarawa, it was Tarawa and Makin both that merely accelerated a program that was already in motion. It was decided to expand the UDT program, but first they would need to be tested, and before that could happen they needed to finish their training.

They were training at Waimanalo Bay on the island of Oahu. At the same time that the NCDU's were operating, the Navy had moved some of the NCDU-trained sailors to the Pacific to build up a beach clearing capacity. There they were combined with members of the Navy Seabees ("CB" or construction battalions), Marines, and Army Combat Engineers and built into larger units christened UDT's, or Underwater Demolitions Teams. The first UDT's were Teams One and Two, consisting of 13 officers and 85 enlisted sailors each. Following their short two-month training, UDT's 1 & 2 were assigned to Task Force 52 (UDT-1) and Task Force 53 (UDT-2) and deployed to take part in Operation Flintlock; the invasion of the Marshall Islands in January of 1944.

Unlike their later teams, the early UDT's were not manned by combat divers; holding true to their NCDU roots they were meant to operate from landing craft in heavy boots and helmets and were tethered to the boats. During the Kwajalein portion of the Marshall Islands invasion this doctrine started to change when two members of UDT-1 stripped down to swimming shorts and swam ahead of a boat to scout out coral heads after the coxswain had determined he could go no further. Following their foray to the beach and back they reported back to the Admiral in charge of the entire invasion and recommended the Marines be sent in Amtrak amphibious tanks instead of boats. The initial assault with Amtracks went well, and later reinforcements at high tide were done with boats (which could carry more and were faster) because of the information they had obtained. The success UDT-1 had with swimmers lead to the adoption of this tactic and it saw widespread use throughout the war and beyond.

Following their initial report and subsequent assault, UDT-1 blew channels in the coral to allow the larger LST's (Landing Ship, Tank) to unload their cargo and cleared out japanese wrecks dotting the shores. On a couple occasions they were sent inland to help the Army clear out strongly fortified bunkers. After Kwajalein UDT-1 went to Engebi island next door and scouted a 400 yard section of beach, blowing coral reefs that would block landing ships and marking positions of Japanese pillboxes on their captured Japanese maps. That night The pillboxes the UDT had marked were bombarded by the fleet surrounding the island. The landing the next day went very well. Lieutenant Luehrs of UDT-1 prevented a major setback when he raced under fire over to a group of Amtracks that were starting to head outside of the marked lanes into uncleared territory.

UDT-2 participatedd in the invasion of Roi-Namur, next to Kwajalein. The night before the invasion members of UDT-2 performed a reconnaissance of the beach and reef via rubber boats and found the beach clear of obstacles and the coral low enough that it would not pose a threat to the landing craft. Like UDT-1, they attempted to use drone landing craft to blow large holes in the coral safely. Like UDT-1's drones, Two's failed as well (one circling around and ramming the craft it was under control from). Their main piece of equipment a failure, members of UDT-2 rode in with the Marines in the first wave and helped by blowing bunkers and dynamiting coral heads that blocked the larger LST's from beaching.

While the two UDT's were off proving themselves, other improvements were made to the program. The training base in Waimanalo was shut down and a new base in Kihei on the island of Maui was established in February, 1944 that would serve the UDT's for the rest of the war. The Waimanalo base had been full with just two teams of 100 men; the new "Underwater Demolition Training and Experimental Base" at Kamaole Amphibious Training Base was training thirteen teams at once at it's peak in late 1944. After the Normandy landing in June of 1944 all Fort Pierce graduates were sent to the Pacific after graduation and all new teams were created as UDT's. By the end of the war there had been over thirty UDT's in the US Navy, with plans to expand up to UDT-60. Of those, all but two received training at Maui, and three skipped Ft. Pierce and trained soley on Maui.

Following Operation Flintlock, UDT's 1 & 2 were deactivated and sent to Maui, some to run training for new UDT teams and others to form the new UDTs being created. Teams 3, 4, 5, 6, and 7 were the first created, in March, and trained for the expanding war in the Pacific. Draper Kauffman had managed to get himself assigned to a combat zone and took over command of UDT-5 and later overall command of three of the UDT's that would operate in the the invasion of Saipan. During the training and build up for this invasion lessons learned and new requirements forced the development of new tactics and equipment.

String Reconnaissance was one such technique. A large amount of fish line was tied off with unique knots at a regular distance so that a diver could tell how much line was played out by the knot they had in their hand. The container of the line was anchored at a known point, and using the distances from that and references from the beach, Divers were able to mark depths and notes on a board with a grease pencil. The results from all the divers were later combined and tabulated, giving an accurate representation of the underwater beach contours and obstructions. The swimmers also had their bodies painted with black lines every six inches so they could accurately gauge depth and report it in a usable fashionn.

One swimmer would swim in a straight line, measuring depth and writing measurements down on a sheet of plexiglass while the other would swim in zig-zags, looking for obstacles and coral heads. "Flying Matteresses" were tried, small powered rafts that would theoretically allow a team leader to work with all of his swimmers during the mission. In practice these turned out to be very dangerous and never saw action beyond Saipan.

Good news for the UDT teams was the arrival of APD's or Auxiliary Personnel Destroyers, which were the high speed transport they were attached to during invasion actions. UDT's 1 & 2 had gone to war in transports that could not support them during landings and contained hundred of troops, the new, fast APD's were equipped with 5" guns and could provide limited support during a landing. The early APD's were converted WWI flush deck destroyers which were cramped and left almost no room for exercisee or training. The second generation were converted DE or Destroyer Escort ships, which were newer, faster, and had enough room for exercise at least, if not comfort.

The assault at Saipan, the first planned daylight assault using many swimmers, went off well. There were more lessons learned and tactics developed, but the feared massacre of swimmers in broad daylight had failed to happen. It had been proven that the best way to gather intelligence on enemy beaches was by having swimmers map the entire landing area in daylight, leaving the protection of their boats and darkness behind.

The UDT's soon established a reputation within the fleet. To everyday sailors they were daredevils who faced the japanese out in the open away from a ship with only a knife and swim trunks. To the admiralty they were a necessary evil, short on decorum but totally effective in their results. Team pride was high; some teams crept up to beaches and left signs welcoming the invading US Marines to the island even before the invasions began. During the invasionn of Guam, for example, UDT-4 left a sign on the beach near the town of Agat that read:

The UDT's proved their worth again on Guam; over 940 obstacles were removed in six days of operations.

In June of 1944 Operation Forager started. The Marianus island chain, defended by roughly 60,000 Japanese, were needed to serve as a base for operations against the Japanese mainland and Japanese-held territories. Of the three islands in the chain, Saipan was first. UDT's 3, 4, 5, 6, and 7 were dispatched to take place in this operationn. Several positive improvements came out of the Marianus operation. High speed drop off and pickup of swimmers using cast and recovery was used. Masks and swim fins had been widely used for the first time. New methods for transporting explosives to the beach from the ships were developed.

UDT-10 and the USS Burfish SS-312 performed reconnaissance on the Islands of Peleliu and Yap in August of 1944. This was the first time Navy special forces deployed from a submarine. Indecision on the part of Navy high command created a need for more information on the two islands in order to determine which of the two was more suitable for invasion. Peleliu was scouted successfully on August 9. On the 16th, Yap was scouted, also successfully. On the 18th Gagil Tomil was scouted and a barrier reef was immediately found. Leaving the boat and one member behind, four members swam ahead, although one later returned, unable to handle the strong currents sweepingg the reef. The three remaining members were never seen alive again, and intercepted communications later indicated they had been captured by the Japanese troops manning the island. No record of them was ever found and it is thought they were put on a boat back to Japan that was subsequently torpedoed by an unknowing American submarine. Due to the information this team gathered, the island of Yap was deemed too costly and was bypassed; without reinforcements the Japanese garrison on the island withered until the end of the war.

After Forager, the invasion of the Carolinas Islands was the next large deployment of UDT personnel. UDT's Able, Six, and Seven were dispatched Disaster struck before the invasion however, when APD-24 USS Noa, carrying UDT Able, was rammed by another American destroyer and sunk with the loss of all of Able's equipment. They were subsequently broken up and sent to other teams to help with staffing

The invasion of Okinawa was the largest deployment of Naval Special Forces, with almost 1,000 UDT personnel participating. UDT's 7, 11, 12, 13, 14, 16, 17, 18 participated.

The invasion at Luzon in the Philippines was another large operation, with UDT's 5, 8, 9, 10, 14, and 15 participating.

Most of the UDT Teams were marshalling in California in preparations for the planned invasion of the Japanese homeland when the war ended. Some were sent to Japane to aid in the occupation.

With Japan's surrender in August of 1945, the majority of the UDT's were shut down. There were a couple that continued to operate in the Pacific, helping allied forces occupy Japan and its former conquested lands. UDT-21 was the first American Forces to land on the Japanese homelands and received the first surrender, when Lieutenant Commander Edward Clayton accepted the sword of a Major in the Coastal Artillery. He was made to turn it over though, lest he steal Army General Douglas MacArthur's limelight.

With the end of the war, the need for the UDT's was seen as negligible and the 34 teams were cut down to 4. See the below table for a listing of the UDT's and their actions.

UDT Teams in WWII
UDT Able	Activated:1944 Deactivated: October/November 1944 History: Deployed as part of the Peleliu invasionon. Attached to APD-24 USS Noa, which was struck by USS Fullman and sunk. There was no loss of life, but as all of their equipment was lost with the ship UDT able did not take part and was sent back to Maui to be broken up and used to help form new UDT's Notes: formed by consolidating several NCDU's that had been deployed to the South Pacific theatre
UDT 1	Activated: December, 1943 Deactivated: February, 1944 History: January 31, 1944 Operation Flintlock, invasion of the Marshall Islands. Performed a failed action with drone boats designed to blow holes in coral reefs and scouted a reef and sea wall ahead of the main landing. February one they blew a channel through the reef to allow larger vessels up to shore. Deactivated afterwards and personnel sent to maui to provide training and leadership for new UDT's.
UDT 2	Activated: December, 1943 Deactivated: February, 1944 History: Operation Flintlock, participated in the invasion of Roi-Namur Island. Team was split up and attached to two ships, one unknown possibly an APA, and the other APA-35 USS Callaway. Upon arrival at the island chain they were off loaded onto Ennuebing Island (Code-named "Jacob" and operated from there. Performed a midnight reconnaissance of a reef and seawall by small boat.
UDT 3	Activated: March, 1944 Deactivated: History: Marianus Invasion, June-July 1944. While originally embarked on APD-9 USS Dent, Team 3 transferred to APD-21 USS Dickerson due to mechanical failure. UDT-3 was held in reserve during the Saipan invasion and not used. Original invasion of Guam was postponed and the Dickerson and UDT-3 waited waitied for fifteen days before returning to Eniwetok for resupply. Redeployed on the 10th of July, 1944, UDT-3 performed reconnaissance on two beaches and a diversionary recon of a beach on July 14. One of the rubber boats came under machine gun fire and three members were missing until being picked up offshore over six hours later. Enemy and friendly fire had forced them to leave the edge of the reef and swim for five hours before they had been picked up. On July 15th two beaches were recon'd and another two had diversionary reconnaissance performed. One Team member was killed by small-arms fire when the LCVP he was traveling on grounded on an underwater coral head for a short time. The next day another diversionary reconnaissance was performed. From July 17 until the 20th over 600 japanese obstacles were blown by a combined total of over 10,000 of tetrytol. Each obstacle was blown by a hand-placed charge that UDT members had placed after either swimming up to or running to across a dry reef. For their actions each enlisted member of UDT-3 was given a Bronze Star and each Officer a Silver Star. Following the invasion UDT-3 removed obstacles and wrecks from around the landing beaches. Following Guam, UDT-3 was attached to APD-7 USS Talbot on October 12 and sent to augment the forces participating in the invasion at Leyte. Storm conditions slowed Talbot's progress and Team Three had to start operations without the benefit of supporting fire. On October 18th Team 3 made a survey of the waters between San Jose and Dulag while under machine gun and mortar fire with no casualties. Platoons 1 & 3 performed the reconnaissance while Platoons 2 & 4 waited in reserve. Team members surveyed right up to the beach, which was judged suitable for landing, and were picked up by their LCPRs 400 yards off shore. The entire operation had taken just over an hour. On October 21st a sandbar at the mouth of a river just south of Dulag was surveyed for possible removal by explosives but was judged to be an impractical project. Following actions at Leyte, UDT-3 transferred to AP-39 President Hayes at Seeadler Harbor for the trip back to Maui. Hayes did not leave for ten days after Team three embarked and they were able to fill their time at the Fleet Recreation Beach in the harbor. Arriving on Maui on Thanksgiving day, members were given another short period of leave before settling in to run training for Teams 12-22. Members of Team Three provided much needed experience and ideas and served in the role of teachers until April of 1945, when they were ordered back to Fort Pierce to aid in training and research there. Members were given a short period of leave stateside before reporting to Fort Pierce on May 1. Team 3 was at Oceanside, California training for the planned invasion of the Japanese homeland when the war ended. Following the capitulation, Team 3 participated in the occupation of Japan while attached to APD-42 USS Gantner. Ganter entered Tokyo Harbor on September 4, 1945 and UDT reconnoiterred the beaches of Shiogama Wan and Ominato Ko on the Japanese main island of Honshu. UDT 3 surveyed the harbor of Otaru, Hokkaido from September 30 to 7 October. Notes: Originally staffed by members of UDTs 1 & 2 after returning from Operation Flintlock
UDT 4	Activated: March, 1944 Deactivated: History: UDT-4 was present at Eniwetok during the Marianas Invasion, June 1944 but was a reserve force in case UDT-1 or -2 was unable to perform their mission. Operated at Agana beach While attached to APD-56 USS Loy, UDT-4 operated during the Okinawa invasion at Ie Shima between March 27-April 23, 1945. Initial beach reconnaissance was performed in late March and UDT-4 was present on the day of the main invasion on April 1 and for the rest of the week. Invasion of Saipan June, 1945 while attached to the USS Kane APD-18. Agana Bay, Guam on 17 July. Team Four blew many "cribs;" coral filled obstacles made with palm logs and linked to each other by cables. Team Four also left a sign on the beach prior to the first landing that read, "Welcome Marines AGAT USO two blocks Courtesy UDT-4." One of UDT-4's boats was hit by mortar fire and sunk at Leyte on 18 October. UDT-4 disembarked Kane on the Admiralty islands in Late October/ Early November.
UDT 5	Activated: March, 1944 Deactivated: History: Marianas Invasion, 1944. While attached to APD-11 Gilmer UDT-5 scouted beaches on Saipan on 14 June. Operations on Tinian in July 14, 1944 were unsuccessful when heavy surf conditions forced abandonment of explosives. Peleliu invasion, September 1944. While attached to USS Humphreys APD-12 UDT-5 operated at the Leyte invasion starting 18 October, 1944. Operated in the Luzon invasion at Lingayen Gulf on January 7 1945 performing beach Reconnaissance while attached to the USS Gilmer. About 2,000 yards (more than a mile) of beach were scouted in about two hours. The next day some diversionary landings were conducted to confuse Japanese forces as to which beach the landings would take place at. Following the landings UDT-5 was transported to the Maui base and given leave. UDT-5 reformed at Fort Pierce at the end of April, 1945 with new members and was in training when the war ended. They were attached to APD-95 USS Hobby and sent to help with the occupation of Japan. October 2-10, 1945, UDT reconnoiterred beaches at Hiro Wan onthe japanese main island of Honshu. October 11, reconoitered the beaches at Mitsuhama on the island of Shikoku.
UDT 6	Activated: March, 1944 Deactivated: November 2, 1945 History: UDT-6 was attached to APD-31 USS Clemson for most of their operations. UDT-6 participated in the Marianas islands Invasion: during the Saipan invasion in June UDT-6 was kept in standby and performed no landings. The next month UDT-6 saw action at Guam on July 17th when they blew ramps in a reef of Dacli beach, creating an area roughly 700 feet wide that craft up to LCT size could use. UDT-6's next operation was the Peleliu invasion, September 1944. After UDT Able's APD was sunk and all equipment lost Team Six added their duties to their tasks in addition to their previous assignment. Performed initial beach reconnaissance under machine gun and sniper fire September 12 and follow-up demolitions the following two days removing coral heads as well as braced obstructions. Operations were conducted while under enemy fire, within fifty yards of Japanese positions without a single casualty. Danger is not confined to the landings and Team Six was put in harm's way one night at Manus Harbor when tetrytol explosives being transferred from another ship caught fire on deck. Demo's of Team Six showed their bravery by picking up the flaming explosives and throwing it overborad before it could damage the ship or cause an explosion. On September 27th UDT-6 reconnoiterred the narrow straight between Peleliu and the smaller Ngesebus island, which had an unfinished airstrip and was assaulted and taken the next day. Philippine invasion (vague information). UDT-6 participated in the occupation of the Japanese homeland while attached to APD-76 USS Schmitt. Reconnoiterred Sasebo Harbor, Japan on 20 September. Miyako Shima Sakishima Gunto was reconnoiterred two days later, where such intense minefields were found that landing operations were cancelled. Following this operation UDT-6 returned to the United states where they were decommissioned on 2 November, 1945.
UDT 7	Activated: March, 1944 Deactivated: History: Marianas Invasion: Saipan in June 1944. Attached to APD-10 Brooks and then APD-6 USS Stringham II. Performed reconnaissance on two potential landing spots on Tinian Island on July 10, 1944. July 24 UDT-7 took part in a daylight fake landing to divert Japanese attention away from the real landing. 12 September, 1944 during the Peleliu invasion UDT-7 cleared paths through minefields. Rotated to the Underwater Demolition Training and Experimental Base in Kihei, Maui to run training for new UDT teams after Peleliu. Several members of UDT-7 showed their calm under fire during this trip when transferring unused tetrytol explosive from Stringham to UDT-6 on the USS Clemson. At one point at anchor at Manus fire broke out amongst the tetrytol aboard one of the ships and was quickly spread to the other ship. Sailors from both ships began jumping overboard, fearing a catasrophic explosion but members from Team Seven and Six quickly began throwing the burning explosives overboard and preventing catastrophy. Deployed again during the Okinawa invasion in April of 1945 on board APD-51 USS Hopping. One member killed and several wounded when the Hopping was taken under fire by a Japanese shore battery and hit several times.
UDT 8	Activated: June, 1944 Deactivated: History: Held in reserve for Pelelui invasion September 12, 1944. UDT-8 cleared approaches to Angaur beach landings in September of 1944. On September 14 Blue beach was reconnoiterred as a diversionary raid; two mines were found and detonated and the beach and defense positions charted. Red beach was scouted the next day and was found to have deep water and a good approach but steel rail obstacles emplaced. These were blown by Team Eight later that day while under the protection of a barrage of ship-based fire. The day after UDT-8 scouted for mines and blew channels in the coral to allow landing craft better and safer access to the shore. Took part in the Leyte invasion in October 1944 while attached to APD-33 USS George E Badger. Team Eight was active in the Luzon invasion January, 1945. Operating on the northern beaches of Lingayen Gulf while attached to the Badger, UDT-8 performed two beach reconnaissance missions for mines and obstructions and charted the beaches with no opposition. Rotated to the Underwater Demolition Training and Experimental Base in Kihei, Maui to run training for new UDT teams after conclusion of the Luzon invasion.
UDT 9	Activated: June, 1944 Deactivated: History: Leyte landings in October 1944 while attached to USS Brooks APD-10. UDT-9 took casualties. Transferred to APD-34 USS Belknap while the Brooks was in for repairs and took place in the Philippine Luzon landings at Lingayen Gulf in January, 1945. Performed reconnaissance on the south end of the gulf on January 7th while under light enemy fire with no casualties. On January 11th members of Team Nine killed 13 Japanese combat/suicide swimmers who were operating in their area, on one case two swimmers tried to throw a grenade into their LCPR while being "rescued." The next day, after several hours of an attack, the Belknap was hit by a Kamikaze and set afire. UDT losses were eight dead, three missing, and thirteen wounded. Additionally nearly all of their equippment had been destroyed. Survivors were transferred to USS Sands APD-13 and sent back to Pearl Harbor and from there they rotated to the Maui camp to run training for the new teams until May. Following that, all members were given a month's leave and told to reform at Fort Pierce in June. Of the original 100-man unit, only 3 officers and 20 enlisted sailors were deemed to be in good enough mental and physical condition to comtinue service as UDT. After replenishment of personnel and retraining, UDT-9 was attached to APD-55 USS Laning and deployed to the far east to aid in landings in Japanese-held lands to help remove the occupying forces. Arrived at Jinsen Harbor Septmeber 9th and performed a quick recon via armed LCVP with no resistance. Deployed to Taku Bar, China next and performed a quick harbor reconnaissance via boat on the 29th of September. Following this reconnaissance the USS Lanning remained at Taku until receiving orders to Tsingtao, China. Arriving October 9th, UDT 9 conducted an armed reconnaissance of the harbor in LCVP's with no reisistance encountered. Following this UDT 9 was sent back to the states and deactivated.
UDT 10	Activated: June, 1944 Deactivated: February, 1946 History: Members of UDT-10 participated in the only submarine operation by UDT in WWII. While deployed on SS-312 USS Burfish five members of UDT-10 scouted the waters and shores around Peleiu’s southeastern tip on 9 August, 1944. On 18 August they performed a reconnassaince of Gagil Tomil’s northeast coast and found a barrier reef. Two members of UDT-10 and one from the Underwater Demolition Training and Experimental Base were captured and executed after being tortured. Article here. While attached to USS Rathburn APD-25, UDT-10 scouted approaches to Angaur beaches September 14th & 15th. East beaches scouted the 14th were found to be clear of obstacles and lightly defended but subjected to heavy currents. North beaches the next day were clear of obstacles and defense and no further action was required of them. Following this Rathburn headed for Ulithi, where they were tasked with clearing and marking five beaches for assault within three days. UDT-10 reconnoitered the Falalop and Asor beaches beginning September 21st and the following three the next day. No obstacles or enemy forces were found. Afterwards members assited the Beachmaster with landing operations. Ulithi became a main US Naval base for the remainder of the war, being a ring of small islands forming a protected anchorate neary 180 square miles in size and having the capacity to hold up to 1,000 large ships at once. UDT-10 assaulted "Red Beach" at San Pedro Bay between Palo and San Ricardo during the landings in Leyte Gulf on October 19th, 1944. On January 7th, 1945 UDT-10 scouted Blue Beach in Lingayen Gulf and destroyed natural and manmade obstacles with demolitions. Performed a nighttime reconnaissance mission without incident two weeks later on January 26th. Landed at San Nareiso on Luzon on the 29th of January and found no opposition. Created a forward training base for UDT's on Guam in Feburary of 1945, then rotated to the Maui base in May. Sent back to the US in June and all team personnel given leave until July 1, at which time the unit reformed at Fort Pierce. Shortly thereafter the war ended and UDT-10 stayed on to help disestablish Fort Pierce until it was deactivated in February of 1946.
UDT 11	Activated: Deactivated: History: Okinawa, Cleared a beach of pointed spikes. Cleared remainder of a beach Team 16 had been tasked with and stayed on to guide invading forces in. Balikpapan, Borneo in early July, 1945 Notes: Team 11 was awarded a Presidential Unit Citation for its actions at Borneo, one of two UDT's in WWII so honored.
UDT 12	Activated: Deactivated: History: While attached to APD-47 USS Bates, UDT-12 participated in the invasion Iwo Jima from February 16 until March 4 of 1945 . One member was missing in action and later declared killed; his body never found Participated in the invasion of Okinawa from March 25th to May 25th when the USS Bates was sunk by Japanese Bombers. From 4, September until 15 September, 1945 UDT operated in Korean waters attached at Jinsen (now Inchon) to APD-45 USS Amesbury performing beach reconnaissance for the occupation of Korea and removal of Japanese forces. Notes: Team 12 was awarded a Presidential Unit Citation for its actions at Iwo Jima, one of two UDT's in WWII so honored.
UDT 13	Activated: July 1944 Deactivated: November 3, 1945 History: UDT-13 was formed from members of Training Class Seven, Fort Pierce. One member killed during an accident January 29, 1945. Ray LeBlanc was welding a fitting over the side of a ship when a wave from a passing wave splashed against the side of the hull, grounding his welding gear and electrocuting him to death or unconsciousness. His body was recovered but he had died either to electrocution or drowning subsequent to electrocution. While attached to APD-39 USS Barr UDT-13 were the first to operate at Iwo Jima, setting up a navigational light while under fire on Higashi Iwa on February 14, 1945 (Also leaving a sign with large red letters that read "750 miles to Tokyo"). Japanese fire soon destroyed the light and they returned two days later to replace it. On February 17 ten swimmers from UDT-13 reconnoitered Green Beach 1 and Purple Beach 2 on Iwo Jima and found no obstacles (water was reported as being 59ºF. One member was missed during pick up and was picked up by a UDT-12 boat which returned him to the Barr. Boat team Baker lead US Marines onto the first beach on D-Day, February 19. A reconnaissance mission to explore the possibility of taking Mount Suribachi from the sea on it's south side. Two members of the 5th Marines reported the south face as too steap for action. Subsequently Team 13 aided Teams 12 and 14 in removing wrecked landing craft cluttering the beaches and towing them out to see for sinking (performed this mission until March 3, 1945). Team 13 was the only UDT that suffered no casualties during the invasion. Team 13 was dropped off at Asor Island, Guam for a couple days of R & R. Despite being in the middle of the ocean the demolitioners proved to be resourcefull and as full of play as they were dedication. In one instance a snowball fight erupted using beer cans as substitutes for snow balls. Other members snuck away from campt and brewed up some alcoholic "Jungle Juice" which was then smuggled aboard the Barr in the landing craft water casks. UDT-13 also participated in the Okinawa landings. March 25th, 1945 saw members reconnoitering the beaches at the southwest tip of Tokashika Shima, a dangerous job as the landing beach was in a cove surrounded by easily defensible high ground. No demolition was required as troops were going in by AMTRAC. March 28th a channel was blown in a reef on Keise Shima after two and a half days of placing explosives. Over 27 tons of explosives had been laid and the shot went off at 1610, creating a channel 100 feet wide and 300 feet long. March 30th members were taken under fire by three US aircraft around 0900, no one hurt or killed despite machine gun fire and bombs. D-day April 1. UDT-13 was transferred from Bar to APA-54 USS Wayne on April 6-7 and returned to Kihei, arriving later that month after a long journey through many ports. Disaster nearly struck during the transfer to Wayne when a Kamikaze came close to hitting the Barr when her fantail was loaded with the UDT's explosizes. Notes: "Lucky number 13", Team 13 had a black cat as a mascot, 13 officers, had taken 13 days to transit from Fort Pierce to Maui, and was attached to APD number 39, which is the product of three times 13.
UDT 14	Activated: 9-15-1944 Deactivated: 10-20-1945 History: While attached to APD-78 USS Bull participated in Lingayen Gulf (Luzon, Philippines) landings. On January 7th UDT-14 scouted the beaches at the North side of Lingayen Gulf under light sniper fire with no casualties. Invasion of Iwo Jima (14 February-5 March); and seizure of Okinawa (21 March-22 April, 2-8 May, and 29 May-1 July). Reportedly members shot down two Kamikaze's during the Luzon operation with .50's they had mounted on the Bull (Not verified). Rotated back to the United States in June of 1945 and was tehre until War's end. Notes: One of the three "Fleet Teams" made up of volunteers with at least one year combat experience and put through a compressed six-week training schedule in Kihei, Maui. In a little over one year of service, UDT 14 received 11 Silver Star medals, 81 Bronze Star Medals with the combat V attachment, a Navy Unit Commendation, a Presidental Unit Citation, Commendation from Commander Amphibious Group 2, Commendation from Commander Amphious Force; Commendation from Commander UDT-14 (after reassignment), and three Purple Hearts; one posthumously.
UDT 15	Activated: September, 1944 Deactivated: October 29, 1945 History: While attached to APD-48 Blessman Participated in landings at Lingayen Gulf (1-19 January 1945) where two beaches (West Flank Green Beach and East Flank Yellow Beach) were scouted with little to no enemy fire and no casualties by platoons One and Two. On January 11th high surf at the primary beaches necessitated finding alternates and Team 15 was called to scout a 3,000 yeard beach. Conditions there were no better and recovery operations failed to pick up four swimmers, three of whom were stranded on the beach with twelve-foot waves pounding the shore, and the last who was picked up by LST 627 (Landing Ship, Tank). A rescue attempt for the three swimmers on the beach failed when the rescue craft capsized in the surf. The Blessman was ordered to join a convoy leaving the area immediately and further rescue operations were halted. The three swimmers managed to make it out past the surf the next morning and were picked up by LSM 11 (Landing Ship, Medium). They were transferred to the USS Humphreys temporarily which delivered them to the USS Blessman (information in this is vague, I am not completely certain they were transferred to the Humphreys or when they were reunited with their teammates). Iwo Jima (14-19 February). Twenty swimmers from Team 15 performed to beach surveys at Iwo Jima, one diversionary, on February 17. During an air attack off Iwo Jima, 18 February 1945, Blessman was hit by a kamikaze (Twin-engined "Betty" Bomber)and took heavy casualties, including 18 UDT members killed and 23 wounded. This was the single largest casualty taken by any UDT or SEAL team since their inception. Following this the team was sent back to Maui, and then back to the United States mainland in June of 1945. Following Japan's capitulation they were embarked on APD-74 USS John Gray and deployed to Jinsen, Korea to aid in landings there. No assistance was needed and UDT was sent back to the United States unused, where they were decommissioned in October of 1945.
UDT 16	Activated: September-October 1944 Deactivated: History: Okinawa, one member killed 3-25-1945 Notes: One of the three "Fleet Teams" made up of volunteers with at least one year combat experience and put through a compressed six-week training schedule in Kihei, Maui
UDT 17	Activated: September-October 1944 Deactivated: History: Okinawa, March of 1945 while attached to APD-87 USS Crosley. Occupation of Japan Notes: One of the three "Fleet Teams" made up of volunteers with at least one year combat experience and put through a compressed six-week training schedule in Kihei, Maui
UDT 18	Activated: September-October 1944 Deactivated: Late October/Early November 1945 History: Okinawa, Borneo, Occupation of Japan (Yokosuka Naval Base) while attached to APD-104 USS William J. Pattison having embarked on August 17 at Guam.
UDT 19	Activated: September-October 1944 Deactivated: Operations: While attached to USS Knudson, UDT-19 performed reconnaissance and demolition operations on Kuba, Aka, Keise, and Geruma Shima from 25 March to 30 March, 1945.
UDT 20	Activated: Deactivated: History: While attached to APD-130 USS Cook UDT 20 saw action in the Japanese occupation after the war. On September 27, 1945 UDT 20 performed reconnaissance of the harbor at Hakodate, Hokkaido with no reisitance. USS Cook departed Japan on 18 October and UDT-20 was disembarked upon the return to San Diego on November 13.
UDT 21	Activated: October, 1944 Deactivated: History: Okinawa invasion while attached to APD-79 USS Bunch in late March / Early April, 1945. Hagushi beaches White 1, 2, and 3 reconnoitered March 29. Log obstacles at beaches Orange 1 and 2 demolished on March 30. Participated in rescue of survivors of APD-21 USS Dickerson who had sank after two Kamikaze hits; UDT-21 members dove over the side of the Bunch and towed survivors to safety despite a continuing battle overhead. Ie Shima invasion April 13 to 21. Beaches Red T 1 and Red T 2 reconnoitered April 13 and Red T 3 and Red T 4 on April 14. No obstacles were found but existing reefs made passage impossible for anything other than tracked vehicles and so it was decided that UDT-21 would clear a channel through the reef at Red T 3. UDT-21 lead army soldiers onto Red T 3 on April 16 and began to blow a channel in the reef for LSM and LST's to use to beach their heavy gear. Over four days thirty-eight and a half tons of explosives were placed by hand on the reef and a channel created while under Japanese fire. Operated on five different islands in June of 1945. On June 6 Team 21 performed reconnaissance on beaches at Iheya Island but no demolition was required. They moved to Aguni Island later that day and operated there until the 9th of June, blasting a seawall and reef to assist in the landings there. The Team traveled back to Okinawa and surveyed wreckage in Naha harbor on June 11th and 12th. Over 80 wrecks were surveyed in the two days Before they were sent back to Ie Shima to improve the channel they'd originally blasted in April. From there they were deployed to Kume Shima on June 26th where they marked channels used in the invasion of that island, which went without opposition. The next day they again went to Ie Shima to finish improvements on the channel there. Following this UDT-21 and the Bunch were released to return to the United States. UDT-21 was preparing for the invasion of Japan when that nation capitualted and the war came to an end. Realizing that they would need to occupy the islands of Japan the Navy rushed UDT-21 to Guam where they were attached to APD-127 USS Begor and sailed for Japan. UDT-21 landed at Futtsu-misaki on the Japanese homeland island of Honshu on August 29, 1945. This was the first landings on the island by american naval forces and also the first surrender ceremony, with Lieutenant Commander Edward Clayton accepting the sword of a Major in the Coastal Artillery in surrender. He was later made to give it up so as not to steal General MacArthur's thunder. Following this the Team cleared docks at Yokosuka Naval Base to allow the USS San Diego to dock there for surrender ceremonies (Picture of the dock here). Japanese ships and facilities were demilitarized by UDT-21 before the US fleet sailed in. The next day, August 31, UDT-21 surveyed Tateyama Beach across the harbor for landing. After this Team 21 was sent back to the United States for deactivation.
UDT 22	Activated: Deactivated: History: While attached to APD-131 USS Young, members of UDT-22 participated in the occupation of the Japanese homeland. UDT-22 first marked three wrecked ships that were navigational hazards. The next day, September 23rd, UDT-22 reconnoitered the beaches at Aomori and the approached to the local highway which were nearby. Several days later a beach at Senami was reconoitered and found suitable, with certain restrictions. Following this the USS Young sailed for the states, and UDT-22 was immediately disembarked upon her arrival on November 2, 1945.
UDT 23	Activated: Jan or Feb, 1945 Deactivated: November 21, 1945 History: Conducted their graduation excercise on the Hawaiian island of Kahoolawe while attached to APD-75 USS Weber in May of 1945. While attached to APD-132 USS Balduck, UDT-23 was deployed to Jinsen, Korea, to aid in landings to remove Japanese after their surrender. No difficulties were encountered and the team spent the duration of the deployment patroling for suicide boats and hiding japanese soldiers. Following return to the United States UDT-23 was decommisioned.
UDT 24	Activated: November, 1944 Deactivated: History: Practice landings (Probably off of Kahoolawe) in May of 1945 with USS Kane. Graduated from teh Kihei base in July and headed to Oceanside, CA. Were in preparation for the invasion of Japan when the atomic bombs were dropped and Japan surrenderred. Deployed to Tokyo Bay aboard the APD-42 USS Ganter after the capitulation. Performed reconnaissance, charting and removal of obstructions for occupational forces at Sagami Wan, Aomori, Otaru, Hakodate in winter conditions. Departed January, 1946 for return to the US and deactivation.
UDT 25	Activated: October, 1944 Deactivated: November 13, 1945 History: UDT-25 was initially formed from returning veterans of the Normandy landings in June of 1944. After training at Fort Pierce Team twenty-five was sent to Maui for advanced training. UDT-25 was then sent to Oceanside, California for cold-water training in preparation for operations on the Japanese homeland. Japan surrendered before the training commenced and the team was attached to USS Knudson which deployed to Tokyo Bay. Knudson and Team 25 rrived on 4 September and stayed until 20 of that same month. The intended reconnaissance of Sagami Wan at Tokyo bay by UDT-25 was cancelled before it began due to two other UDT's (Teams 18 & 21) being assigned that duty before Twenty-Five had arrived. Members of UDT-25 went back to Coronado, California to help set up the permanent Underwater Demolition base before the team was decommissioned.
UDT 26	Activated: Deactivated: History: While attached to APD-43 USS Ingram UDT 26 participated in the removal of Japanese forces from foreign occupied lands. Deployed to Jinsen, Korea, Taku Bar, China, and Port of Tientsin, North China.
UDT 27	Activated: ?? Deactivated: ?? 1945 History: Occupation of Japan. UDT-27 had been preparing for the invasion of Japan when the capitulation precluded their operations. While embarked on APD-106 USS Cobb UDT-27 operated inside Tokyo harbor, reconnoitering beaches and landing areas in preparation for the arrival of other US occupation forces.
UDT 28	Activated: Deactivated: History: I suspect at this point that UDT-28 was training for the invasion of Japan when the war ended. The only note I've found so far on their existance is that they traveled from Pearl Harbor HI to Oceanside CA, July 27-Aug 2 aboard APD-69 USS Yokes. Transferred to LCT-395. It's my belief at this time that they had just finished training at Maui and were headed stateside for cold-water training.
UDT 29	Activated: Deactivated: History: I suspect at this point that UDT-29 was also training for the invasion of Japan when the war ended. The only note I've found so far on their existance is that they traveled from Pearl Harbor HI to Oceanside CA, Aug 2-13 aboard APD-95 USS Hobby. The day after they arrived the war ended. It's my belief at this time that they had just finished training at Maui and were headed stateside for cold-water training.
UDT 30	Activated:July, 1945 Deactivated: October, 1945 History: UDT-30 was training for the upcoming invasion of Japan when the war ended and was soon decommissioned. UDT-30 never trained at the Kamaole Amphibious Training Base on Maui and was only based stateside.
UDT George	Activated: Deactivated: History: UDT George was a purely US Army team who trained alongside their Navy counterparts but never saw action. Compriesed of over 100 men from the US 6th and 8th Armies, UDT George finished their training just before the end of the war and was soon disestablished. UDT George was trained soley at the Kihei training base and never assembled at Fort Pierce.

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