Navy Medium Landing Ship (LSM) Program: Background and Issues for Congress

The Navy’s Medium Landing Ship (LSM) program, previously called the Light Amphibious Warship (LAW) program, envisions procuring a class of 18 to 35 new amphibious ships to support the Marine Corps, particularly in implementing a new Marine Corps operational concept called Expeditionary Advanced Base Operations (EABO). The EABO concept was developed with an eye toward potential conflict scenarios with China in the Western Pacific. Under the concept, the Marine Corps envisions, among other things, having reinforced-platoon-sized Marine Corps units maneuver around the theater, moving from island to island, to fire anti-ship cruise missiles (ASCMs) and perform other missions so as to contribute, alongside Navy and other U.S. military forces, to U.S. operations to counter and deny sea control to Chinese forces. The LSMs would be instrumental to these operations, with LSMs embarking, transporting, landing, and subsequently reembarking these small Marine Corps units. LSMs would be much smaller and individually much less expensive to procure and operate than the Navy’s current amphibious ships. In December 2025, the Navy announced that it had selected the design of the Landing Ship Transport 100 (LST-100)—a design from the Dutch shipbuilder Damen Naval—as the design to which initial LSMs are to be built. LSMs might be built by multiple shipyards. The Navy anticipates that construction of LSMs will begin in late 2026 and wants the first LSM delivered to the Navy by 2029. In the FY2026 National Defense Authorization Act (NDAA) (S. 1071/P.L. 119-60 of December 18, 2025) Section 127 provides the Navy authority to use a block buy contract for the procurement of not more than 15 LSMs; and Section 129(a) directs the Navy, after awarding a contract for the first LSM, to select a vessel construction manager (VCM) (i.e., a person outside the Navy) to manage the contracting for procuring not more than eight additional LSMs. In the FY2025 reconciliation act (H.R. 1/P.L. 119-21 of July 4, 2025, also called the One Big Beautiful Bill Act [OBBBA]), Section 20002 provides $160.0 million for advance procurement of materials for LSMs and $1,803.941 million (i.e., about $1.8 billion) for procurement of LSMs. This funding appears sufficient to procure several LSMs.