The Sea Porpoise was sold to a private owner in 1946 and scrapped in 1971. 

On 5 Jul, 1944, U-390 attacked ships off the Normandy and claimed the sinking of two vessels. The ships hit were HMS Ganilly (T 376) and Sea Porpoise.

At 21.15 hours, the Sea Porpoise (Master Nils Leknes) was hit by one torpedo when steaming at 8 knots as the last ship in the starboard column in a convoy with two columns about 10 miles off Utah Beach. The torpedo struck on the starboard side amidships, threw the shaft out of line, damaged the main turbine, cracked some hull plating and injured twelve men. The nine officers, 81 crewmen, 45 armed guards (the ship was armed with one 4in, four 3in and eight 20mm guns) and 24 passengers (US Army personnel) stayed on board. The ship developed a 10° list to starboard, but this was corrected by counter-flooding.
After four hours, the ship was taken in tow to the Utah Beach and anchored. On 9 July, she was towed to Spithead in two days and later to Newcastle-upon-Tyne for temporary repairs. On 16 September, the Sea Porpoise left under tow in a slow convoy for Jacksonville, Florida, arriving on 5 October. On 4 May, 1945, she returned to service after permanent repairs were completed.