Three days later, SS-400 again headed west. On 16 May, she returned to Subic Bay; and, on 23 May, she continued on to Tsingtao where she provided antisubmarine warfare training services to TF 71 into July. On 5 May, she sailed for Shanghai, whence she proceeded back to Pearl Harbor. From 26 July 1946 to 5 May 1947, she conducted operations in the Hawaiian area. Overhaul at Mare Island took her through the summer. In early October, she returned to Hawaii, and on 27 May, she sailed westward for another tour in the Far East.