The first PBM-1s entered service with Patrol Squadron Fifty-Five (VP-55) of the United States Navy on 1 September 1940.Prior to the USA's entry into World War II, PBMs were used (together with PBYs) to carry out Neutrality Patrols in the Atlantic, including operations from Iceland. Following Japan's attack on Pearl Harbor, PBMs were used on anti-submarine patrols, sinking their first German U-boat, U-158 on 30 June 1942. PBMs were responsible, wholly or in part, for sinking a total of ten U-boats during World War II. PBMs were also heavily used in the Pacific War, operating from bases at Saipan, Okinawa, Iwo Jima and the South West Pacific.
The United States Coast Guard acquired 27 Martin PBM-3 aircraft during the first half of 1943. In late 1944, the service acquired 41 PBM-5 models and more were delivered in the latter half of 1945. Ten were still in service in 1955, although all were gone from the active Coast Guard inventory by 1958 (when the last example was released from CGAS San Diego and returned to the U.S. Navy). These flying boats became the backbone of the long-range aerial search and rescue efforts of the Coast Guard in the early post-war years until supplanted by the P5M Marlin and the HU-16 Albatross in the mid-1950s.
PBMs continued in service with the U.S. Navy following the end of World War II, flying long patrol missions during the Korean War. It continued in front line use until replaced by its successor, the P5M Marlin, with the last USN squadron equipped with the PBM, Patrol Squadron Fifty (VP-50), retiring them in July 1956.
The only surviving Martin Mariner is on display at Pima Air and Space Museum.
Another aircraft (PBM-5 BuNo 59172) lies upside down under Lake Washington. It crashed on 6 May 1949, and after a number of unsuccessful attempts to recover the wreck over the following decades it is now used as a training site for divers. The tail is displayed behind the intact Mariner at Pima