The ship was built at Cook, Welton & Gemmell, of Beverley, England, as part of the 1939 Programme for the Royal Navy.

In July 1941 Begonia was part of the force escorting OG 69, which saw seven ships sunk and one U-boat damaged off the coast of Portugal.

[2] One of a group of corvettes transferred to the U.S. Navy under reverse Lend-Lease, she was commissioned as USS Impulse in March 1942.

Impulse returned to New York on 25 August 1942 for duty protecting the important supply line between that port and Guantánamo Bay, Cuba.

For the next three years she made repeated escort voyages to and from Cuba, effectively helping to counter the German U-boat menace.