She participated in World War II, first on the side of the Allies from 1939 to June 1940, then in the navy of Vichy France until she was decommissioned at the beginning of 1944 and subsequently abandoned.

Propelled on the surface by two diesel engines producing a combined 6,000 horsepower (4,474 kW), they had a maximum speed of 18.6 knots (34.4 km/h; 21.4 mph).

Laid down at Ateliers et Chantiers de la Loire in Saint-Nazaire, France, on 29 September 1928[2] with the hull number Q156, Pégase was launched on 28 June 1930.

[2] Pégase and her sister ship Monge departed Toulon, France, on 16 December 1936 bound for French Indochina in Southeast Asia, which they reached in January 1937.

[3][6] On 11 October 1940, Pégase and Monge departed Bizerte under escort by the Élan-class sloop La Batailleuse bound for Oran in Algeria.

[3] On 16 February 1941, however, Pégase, Monge, and Lot finally departed Diego-Suarez to begin the last leg of their voyage to French Indochina, which they completed without further incident with their arrival at Saigon on 6 March 1941,[3][6] too late to participate in the Franco-Thai War,[3] which had concluded on 28 January 1941.

[6] After the completion of repairs, Pégase and Monge departed Saigon on 15 March 1941 for a two-month cruise to make "representation" visits to ports along the coast of French Indochina.

[3][6] They stopped first at Cam Ranh,[3][6] pausing to hold a memorial service in the South China Sea over the wreck of their sister ship Phénix, lost with all hands in a diving accident on 15 June 1939.

[6] They then visited Qui Nhon and Haiphong in French Indochina and Fort Bayard in Kouang-Tcheou-Wan, China, before beginning their return journey, stopping in French Indochina at Hạ Long Bay, Cape Varella, Tourane, and Cam Ranh before returning to Saigon in mid-May 1941.

In the meantime, Pégase conducted numerous escort missions along the coast of French Indochina, protecting the shipping lanes between Saigon and Haiphong, until June 1942.

[3] Before she could leave, however, the Allied landings in French North Africa in Operation Torch on 8 November 1942 prompted the Japanese to suspend the agreement, then cancel it entirely.

[3][11] Still afloat when World War II ended with the surrender of Japan on 2 September 1945, Pégase′s hulk soon was towed into the Mekong Delta and grounded on a shoal to mark the mouth of the Bassac River.