The second HMS Louis (K515) was a British Captain-class frigate of the Royal Navy in commission during World War II.

The ship was laid down by the Boston Navy Yard in Boston, Massachusetts, on 9 July 1943 as the unnamed U.S. Navy destroyer escort DE-517 and launched on 13 August 1943.

The ship was commissioned into service in the Royal Navy as HMS Louis (K515) on 9 November 1943[2] simultaneously with her transfer.

On 24 August 1944, she sank the German submarine U-445 with depth charges in the Bay of Biscay west of St. Nazaire, France, at position 47°21′00″N 005°50′00″W / 47.35000°N 5.83333°W / 47.35000; -5.83333 (U-445 sunk).

The United States Government sold Louis to the Commonwealth of Pennsylvania on 17 June 1946.