Escolar had her final training for combat at Pearl Harbor, from which she put out for her first war patrol on 18 September 1944.

After topping off fuel at Midway Island, she joined Croaker and Perch for a coordinated "wolfpack" patrol in the Yellow Sea.

Had Escolar ended her patrol on the scheduled date, she would have arrived at Midway Island about 13 November 1944.

Information supplied by the Japanese on anti-submarine attacks gives no clue as to the cause of her loss, but the Yellow Sea area is thought to have been mined.

Her course as transmitted to Perch does not cross any known Japanese minefields, but positions of mines laid before April 1945 are not precisely known.