Naval Base Majuro was a major United States Navy base built on Majuro Atoll, in the Marshall Islands to support the World War II efforts in the Pacific War. The base was built after the Battle of Majuro-Kwajalein ended 3 February 1944. Majuro was found to be unoccupied and abandoned when the United States Army arrived. The US Navy built airfields, a seaport, and other facilities on the captured islands. The base was part of the vast Naval Base Marshall Islands.

The United States Navy built permanent and temporary submarine bases around the world to maintain its fleet of submarines and serve the needs of the crews. Submarine bases are military bases that offer good fleet anchorage and are designed to refuel and resupply submarines. The peak number of US submarine bases was during World War II, as the submarine was well suited for fighting in the vast Pacific War, often in enemy waters. Many of the United States submarine bases were closed after the war.