USS ESCOLAR (SS-294) had her final training for combat at Pearl Harbor, from which she put out for her first war patrol 18 September and proceeded to Midway to top off with fuel. There she joined USS CROAKER (SS-246) and USS PERCH (SS-313) and left on 23 September to conduct a coordinated patrol in the Yellow Sea north of 30!N. Cdr Millican was in command of this coordinated attack group, which was designated "Millican's Marauders."
On 30 September, when ESCOLAR was estimated to be about north of the Bonin Islands, the following partial message was received from her: "This from ESCOLAR X attacked with deck gun boat similar to ex-Italian Peter George five OTYI ----." Although no further transmissions were ever received by bases from ESCOLAR, who was forced to break off the transmission and the engagement with the gunboat at that time, CROAKER had stated that she suffered no damage and was in frequent communication with PERCH and CROAKER until 17 October 1944.
PERCH reported that on 17 October she had received a message from ESCOLAR stating that she was in position 33!-44'N;127!-33'E, and was heading for 33!-44'N;129!-06'E. Neither PERCH nor CROAKER could raise ESCOLAR by radio after this transmission was received.
Had ESCOLAR left her area on the scheduled date, she would have
arrived at Midway about 13 November 1944. All attempts to contact ESCOLAR
failed and she was reported on 27 November 1944 as presumed lost. It
is assumed that she was lost about 17 October. 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. A course
line plotted between the two positions given above does not cross any known
Japanese mine lies, but positions of mines laid before April 1945 are not
definitely located. The known minefields in Tsushima Strait were laid in
April 1945. However, there were mines in the general area of ESCOLAR's
predicted position, and the most likely explanation for her end is that
she detonated a mine.