In production, the Neptune was an impressive platform in size and capability. It grossed out at some 61,000 lb., was powered by two 2,300 hp Wright engines that allowed for a maximum speed of 303 M.P.H., and possessed three .50 caliber machine gun turrets (later converted to 20mm cannon), an enclosed bomb-bay capable of carrying two torpedoes or twelve depth charges, and provisions for sixteen under wing rockets.

Delivered to the fleet in March 1947, P2Vs equipped patrol squadrons during the Korean War, flying railroad interdiction and spotting naval gunfire in addition to their maritime patrol duties. All told, Neptune-equipped squadrons logged thirteen combat tours during the Korean War. In addition, some modified P2Vs were cast as lead players in the Navy's nuclear arsenal, equipping Composite Squadrons (VC) 5 and 6 and operating from carriers as naval aviation's first atomic bombers. The aircraft's capabilities in this role were dramatically demonstrated in 1949 when three P2Vs launched from an aircraft carrier off the Virginia coast with 10,000 lb. of dummy bombs onboard, flew across the continent to the west coast, dropped their bombs, and returned non-stop to Naval Air Station Patuxent River, Maryland.

The final version of the venerable P2V/P-2 Neptune produced by Lockheed, the SP-2H featured under wing jet pods for added power and carried the most sophisticated antisubmarine warfare detection equipment of its day, namely the Jezebel and Julie sonar systems. First flown in 1954, these advanced versions of the Neptune not only played cat and mouse with Soviet submarines, but also participated in mine surveillance and support of operations in the Antarctic. During the Vietnam War Navy patrol squadrons equipped with the SP-2H were heavily involved in support of Operation Market Time, the surveillance and interdiction of waterborne craft in an effort to stem the flow of supplies into South Vietnam. In addition, some SP-2Hs were modified to the OP-2H configuration that carried a Trails and Roads Interdiction Multisensor (TRIM) package. These aircraft equipped Heavy Attack Squadron (VAH) 21, which conducted night interdiction missions over the Mekong Delta.

The SP-2H made its last antisubmarine warfare flight on 20 February 1970. Co-pilot for the flight was Rear Admiral Tom Davies, pilot on the 1946 record-setting flight of the "Truculent Turtle." Following the flight it joined others in service as utility aircraft in Naval Reserve Squadrons.