As of 2021, 86 years after its first flight, the aircraft continues to fly as a waterbomber (or airtanker) in aerial firefighting operations in some parts of the world.

[5] With a mind to a potential conflict in the Pacific Ocean, where troops would require resupply over great distances, the U.S. Navy invested millions of dollars in the 1930s developing long-range flying boats, which had the advantage of being able to land in any suitable waters.

As American dominance in the Pacific Ocean began to face competition from Japan in the 1930s, the U.S. Navy contracted Consolidated, Martin and Douglas in October 1933 to build competing prototypes for a patrol flying boat.

[6] Naval doctrine of the 1930s and 1940s used flying boats in a wide variety of roles that today are handled by multiple special-purpose aircraft.

The U.S. Navy had adopted the Consolidated P2Y and Martin P3M models for this role in 1931, but both aircraft were underpowered and hampered by inadequate range and limited payloads.

[citation needed] Consolidated's XP3Y-1 design (company Model 28) had a parasol wing with external bracing struts, mounted on a pylon over the fuselage.

[7] The prototype was powered by two 825 hp (615 kW) Pratt & Whitney R-1830-54 'Twin Wasp' radial engines mounted on the wing's leading edge.

The Navy requested further development in order to bring the aircraft into the category of patrol bomber, and in October 1935, the prototype was returned to Consolidated for further work, including installation of 900 hp (670 kW) R-1830-64 engines.

These patrol planes shared with land based patrol bombers the combat roles while the very long range Consolidated LB-30 Liberator and the Consolidated Coronado were pressed into service to increase the all important logistic strategic air lift capability in the vast Pacific theater.

While flying to safety during the raid on Cavite, Lieutenant Harmon T. Utter's PBY was attacked by three Japanese Mitsubishi A6M2 Zero carrier fighters.

Chief Boatswain Earl D. Payne, Utter's bow gunner, shot down one, thus scoring the U.S. Navy's first kill.

[15] Catalinas were the most extensively used anti-submarine warfare (ASW) aircraft in both the Atlantic and Pacific theaters of World War II, and were also used in the Indian Ocean, flying from the Seychelles and from Ceylon.

By 1943, U-boats were well-armed with anti-aircraft guns and two Victoria Crosses were won by Catalina pilots pressing home their attacks on U-boats in the face of heavy fire: Flying Officer John Cruickshank of the RAF, in 1944, received the award for sinking what was believed to be U-347 (although now known to have been U-361[17]) and in the same year RCAF Flight Lieutenant David Hornell received the decoration posthumously for the sinking of U-1225.

The aircraft's parasol wing and large waist blisters provided excellent visibility and combined with its long range and endurance, made it well suited for the task.

On 7 December 1941, before the Japanese amphibious landings on Kota Bharu, Malaya, their invasion force was approached by a Catalina flying boat of No.

[24] Flying Officer Patrick Bedell, commanding the Catalina, and his seven crew members became the first Allied casualties in the war with Japan.

Patrol Wing 10 also lost its main seaplane tender, USS Langley, to Japanese aircraft during the Dutch East Indies Campaign while it was transporting 32 Curtiss P-40 Warhawk fighter planes.

[29] During the Battle of Midway, four U.S. Navy PBYs of Patrol Squadrons 24 and 51 made a night torpedo attack on the Japanese fleet on the night of 3–4 June 1942, scoring one hit which damaged the fleet oiler Akebono Maru, the only successful American torpedo attack in the entire battle.

[30] During the Guadalcanal campaign, some U.S. Navy PBYs were painted matte black and sent on night bombing, torpedoing, and strafing missions against Japanese supply vessels and warships, including conducting interdiction raids on the Tokyo Express.

The Black Cats also performed bombing, strafing and harassment regarding land based Japanese installations, as well as conducting reconnaissance and search and rescue operations.

Operations included trapping the Japanese fleet in Manila Bay in assistance of General Douglas MacArthur's landing at Mindoro in the Philippines.

Australian Catalinas also operated out of Jinamoc in the Leyte Gulf, and mined ports on the Chinese coast from Hong Kong to as far north as Wenzhou.

RAAF aircrews, like their U.S. Navy counterparts, employed "terror bombs", ranging from scrap metal and rocks to empty beer bottles with razor blades inserted into the necks, to produce high-pitched screams as they fell, keeping Japanese soldiers awake and scrambling for cover.

A PBY piloted by LCDR Adrian Marks (USN) rescued 56 sailors in high seas from the heavy cruiser Indianapolis after the ship was sunk during World War II.

The aircraft could not fly in this state; instead it acted as a lifeboat, protecting the sailors from exposure and the risk of shark attack, until rescue ships arrived.

For example, Qantas Empire Airways flew commercial passengers from Suva to Sydney, a journey of 2,060 miles (3,320 km), which in 1949 took two days.

[36] An Australian PBY named "Frigate Bird II", an ex RAAF aircraft, registered VH-ASA, made the first trans-Pacific flight across the South Pacific between Australia and Chile in 1951 by (Sir) Gordon Taylor,[37] making numerous stops at islands along the way for refueling, meals, and overnight sleep of its crew, flown from Sydney to Quintero in Chile after making initial landfall at Valparaiso via Tahiti and Easter Island.

[41] Air race champion, stunt pilot, and airline operator Paul Mantz converted an unknown number of surplus Catalinas to flying yachts at his Orange County California hangar in the late 1940s and early 1950s.