Ship status is indicated as either currently active [A] (including ready reserve), inactive [I], or precommissioning [P]. Ships in the inactive category include only ships in the inactive reserve, ships which have been disposed from US service have no listed status. Ships in the precommissioning category include ships under construction or on order.
There have been four generations of amphibious warfare ships, with each generation having more capability than the previous:
The first generation simply landed troops and equipment ashore with standard (i.e., non-specialized) boats and barges. These ships are not listed in this article since they were indistinguishable from the troopships and other surface combatants of their day, and as such were not assigned specialized hull classification symbols.
The second generation was designed during World War II to land personnel and vehicles ashore, either directly or via carried specialized landing craft.
The third generation was designed beginning in the 1950's to use helicopters for amphibious operations, with the result that such operations were no longer limited to beaches.
The fourth generation was designed beginning in the 1980's to use hovercraft (Landing Craft Air Cushion (LCAC) specifically), with the result that the numbers and types of beaches which could be accessed dramatically increased.
World War II
During the naval build-up for World War II, many Maritime Commission (MARCOM) standard designs were converted to US Navy amphibious warfare ships. In the Cold War these and newer standard designs were built under MARCOM's successor agency, the United States Maritime Administration (MARAD):
In the following lists MARCOM types are abbreviated as 'MC type' and MARAD as 'MA type'; 'MC types' became 'MA types' in 1950.
The first amphibious warfare ships had a top speed of 12 to 17 knots. With the appearance of higher speed submarines at the end of World War II, the US Navy decided that all new amphibious warfare ships would have to have a minimum speed of 20 knots (37 km/h; 23 mph) to increase their chances of survival. All new ships with a full flight deck (LPH, LHA, LHD), the Landing Platform Docks (LPD) and the High Speed Transport destroyer conversions (APD/LPR) would meet this criteria. The other major types would see relatively small numbers of new ships constructed with this 20 knot requirement, with the last appearing in 1969.
Amphibious warfare ships were considered by the US Navy to be auxiliaries and were classed with hull classification symbols beginning with 'A' until 1942. Many ships were reclassed at that time as landing ships and received new hull symbols beginning with 'L'; others would retain 'A' hull symbols until 1969 and then receive 'L' symbols. This article pairs the two lists of what are the same ships, with each 'L' list preceding the respective 'A' list. Littoral Combat Ships also use 'L' hull symbols but are not solely intended for amphibious warfare.
In 2015 the US Navy created new hull classification symbols that began with an 'E' to designate 'expeditionary' vessels. Expeditionary vessels are designed to support low-intensity missions, allowing more expensive, high-value amphibious warfare ships to be re-tasked for more demanding missions. Most of these ships are not commissioned warships, but rather are operated by the Military Sealift Command.
The Tarawa-class LHA was the first to combine the features of the well deck of the Landing Ship Dock (LSD) or Landing Platform Dock (LPD) and the full flight deck of the Landing Platform Helicopter (LPH) into one ship. Though not designed to carry Landing Craft Air Cushion (LCAC)s, they could accommodate one in their well decks.
The America-class LHA would be a follow-on to the Wasp-class LHD. The first two ships, America and Tripoli, would not have a well deck, so as to dedicate more space to the support of air operations. This was criticized as a repeat of the mistakes of the LPH concept, and so it was decided that Bougainville and all future ships of this class would have a well deck.
The well deck of the Tarawa-class LHA was not designed to accommodate the Landing Craft Air Cushion (LCAC), which came into service just six years after the last of that class was completed. The Wasp-class LHD and the later units of the America-class LHA were designed to be LCAC compatible; the Wasp-class could carry 3 LCACs.
The Landing Platform Helicopter (LPH) would be the first ships to operate helicopters for large scale air assault behind beaches. One major defect of the LPH concept was that these ships did not carry landing craft to disembark Marines when weather or hostile anti-aircraft systems grounded helicopters; only Inchon would be modified to carry two landing craft. In such situations the LPH would be reliant on landing craft supplied by other ships, which proved awkward in practice. This defect would drive the design of the Tarawa-class LHA, in effect a LPH with a well deck.
As the 'definitive' LPH design, the Iwo Jima class would be the only class to be built as such, with sufficient 'hotel' accommodations for the embarked Marines. All other LPH ships would be conversions of aircraft carriers, and so had accommodation deficiencies (for example, some Marine units could not bunk together, and water distillation was insufficient to allow all personnel showers within a 24 hour period).
The Landing Platform Dock (LPD) concept began as a compromise design, an attempt to build a ship with much more capability than a Landing Ship Dock (LSD) - the LPD superficially resembles an LSD with an enlarged flight deck - but without the expense of a LPH. The well deck is smaller than that of an LSD. The Raleigh and Austin classes could be fitted with a temporary telescoping helicopter hangar.
Several of these ships were built with space dedicated for command capabilities. Two of these, La Salle and Coronado, would be redesignated as auxiliary command ships (AGF).
The San Antonio-class were the first LPDs designed to accommodate Landing Craft Air Cushion (LCAC); two could be carried. They were also the first LPDs to be built with a permanent helicopter hangar.
The LSD came as a result of a British requirement during World War II for a vessel that could carry large landing craft across the seas at speed. The design was developed and built in the US for the Royal Navy and the US Navy, with the US Navy originally classifying these ships as Mechanized artillery transports (APM), then changing them to LSDs. The first LSDs could carry 36 LCM at 16 knots (30 km/h) in a flooding well deck, the first ships with this capability. Late in the war they were modified with the addition of a temporary superdeck over the well deck; this could carry vehicles, support helicopter operations, or be removed for outsized cargo.
In December 2020 the U.S. Navy's Report to Congress on the Annual Long-Range Plan for Construction of Naval Vessels stated that it was planned that all LSDs would be placed Out of Commission in Reserve by 2027.
The Anchorage class was basically the Thomaston class with the well deck enlarged (49 feet longer and 2 feet wider) to accommodate the new larger LCU-1610 class. They would later be modified to carry up to 3 Landing Craft Air Cushion (LCAC).
The Blue Ridge-class would be the only amphibious command ships purposely built as such by the US Navy, and the first and only class capable of exceeding 20 knots. Their hulls were based on the Iwo Jima-class Landing Platform Helicopter (LPH) design due to the need for flat deck space for multiple antennas. After the retirement of the fleet flagships [cruisers] (see also List of cruisers of the United States Navy § Command cruisers (CLC, CC)) these ships would be pressed into that role despite their lack of speed relative to carrier strike groups.
High-speed Transports (APD) were converted destroyers and destroyer escorts; they received the US hull classification symbol APD: "AP" for transport and "D" for destroyer. In 1969, the remaining ships were reclassified as Amphibious transport, small (LPR). This classification is not to be confused with hull code "HST", also for "High Speed Transport", currently assigned only to experimental high-speed catamaran designs, and high-speed catamarans chartered from private ferry companies.
During World War II a number of small boats were built to direct the movements of landing craft as they approached beaches. These were 56 feet in length, displaced 30 tons, and ran 13-16 knots in speed. They were equipped with multiple radios and SO radar (the same radar as on PT boats). During the invasion of southern France they were used to control drone minesweepers.
The United States Navy built the LCU 1466, 1610 and 1627 classes after World War II. Seventy old LCUs (likely ex-LCTs) were retired from amphibious duties and reclassified as Harbor utility craft (YFU).
Towards the end of World War II the United States Navy built 558 Landing Ship Medium (LSM) type vessels across three classes. They were originally designed under the classification Landing Craft Tank - Mark 7 but were reclassified after exceeding 200 feet in length.
As of February 2023 the US Marine Corps has proposed the purchase of 18 to 35 modern LSMs; this LSM concept was previously known as the Light Amphibious Warship (LAW).
Landing ship, tank (LST)
The United States Navy built nearly 1,200 tank landing ships, classified as "Landing Ship, Tank" or "LST", from the World War II-era up through the early 1970s. The Newport class, which entered service in 1969, would be the last class built and the only class capable of exceeding 20 knots. The 1987 introduction of Landing Craft Air Cushion (LCAC) — which allowed for over-the-horizon amphibious landings onto a far larger number of beaches — made LSTs obsolete, but they remained with the fleet for another decade because they were the only means by which the hundreds of thousands of gallons of motor vehicle fuel needed by a Marine Expeditionary Force could be landed. Only the development of tankers with the Offshore Petroleum Discharge System (OPDS) and the later development of special fuel bladders which gave the LCACs a tanker capability allowed for their retirement.
The ATL hull classification was short-lived; it was changed to Landing Ship Tank (LST).
USS ATL-1, later USS LST-1
Vehicle landing ship (LSV)
The World War II LSVs were converted from surplusminelayers (CM) and netlayers (AN) into ships which could carry and launch amphibious vehicles. After the war most were slated to become mine countermeasures support ships (MCS), but only two were actually converted.
Thirty-five PC-461-classsubmarine chasers were converted into amphibious landing control vessel during World War II and reclassified as Patrol Craft, Control after the war. Extra personnel (eight radiomen, two signalmen, one quartermaster and two communications officers), accommodations and improved radar and communications equipment were added. PCs proved exceptionally adept as Control Vessels, guiding waves of landing craft during numerous amphibious landings in the European and Pacific Theaters.
Thirteen Patrol Craft Sweepers (which were built on 134-foot YMS-1-class minesweeper hulls) were converted into amphibious landing control vessel during World War II and reclassified as Patrol Craft Sweeper, Control.
In January 2023, the Navy announced that three Expeditionary Medical Ships (EMS) had been approved in the 2023 military budget. By May 2023 the three ships had been officially reclassified from EPF to EMS.