The fifth and final war patrol of the Bergall began 12 May, 1945 and was conducted, for the most part, in the Gulf of Siam, although she was sent out into the China Sea to perform scouting duties during the invasion of Borneo.

Upon arrival on station, Commander Hyde was appointed coordinator of a wolf pack consisting of the Cobia, Bullhead, Hawkbill and Kraken. This pack spent a month exploring every nook of both coasts of the Gulf of Siam but the Japanese were fast running out of ships. Many small craft were sunk by gunfire and while the Bergall was on a scouting mission off Borneo, two Japanese merchantmen were sunk by the Cobia's torpedoes. In a gun action on the night of 13 May, the Bergall sank two small tugs and five barges. Then on 12 June, the convoy which the airmen had been promising the Bergall for five days was finally sighted. At 1130, while patrolling submerged, two small AO's and one small AK was escorted by a single PC (patrol craft) scraped their way along or upon the coast, it was never determine which. The Bergall was not able to close range to less than 5,000 yards without getting herself in water less than 60 feet deep. The approach was broken off, and the convoy was trailed with the intention of attacking at night when she could get into water nearly as shallow as the convoy was sailing.

The second section had the mid-watch. The Bergall was searching every possible anchorage along the coast, often moving into water which was less than a fathom under her keel. Somewhere the convoy must have holed up for the night.

The 13th of June began black; there was no moon. In being relieved, Buddy Specht (Nebraska) had said to Kenny Smith (New York), 'Well Smitty, it’s the 13th, we ought to get in some kind of jam soon." Smitty didn’t have long to wait. At 0110 about a mile off the Burma coast a mine exploded, fortunately off to one side, lifting the stern end of the Bergall three or four feet, tripping out all propulsion, jamming the rudder full left, tossing several of the crew and one of the torpedoes out of their "racks" in the after room and sheering any number of bolts of all sizes. Later, the major damage was discovered to be a bad knock in the port reduction gear, but in the immediate peril this was of no interest. The Bergall had been shelled, bombed and depth-charged till one more explosion meant little more than extra work for all hands. Within a few minutes of the explosion the Maneuvering Room had give the Bridge propulsion on the after battery, and the Control Room had gotten the rudder off the stop. Twenty minutes later (0130) the crew had their ship underway on one shaft (starboard), had two engines on propulsion and the rudder operating in power. Investigation the next morning showed that the noise of the port reduction gear made submerged approaches impossible. Also the real extent of the damage might easily exceed the visible symptoms. It was decided to return to port.

It was later revealed that the mine had also twisted her stern torpedo tubes out of alignment. The mine was believed to have been remotely exploded and this would explain the distance from actual contact with the mine.

Thus the Bergall ended her wartime career. From Subic Bay she was sent to Sub-Pac and Sub-Pac sent her to Portsmouth, New Hampshire, where she arrived 5 August, 1945 and where a few days later when the Japanese capitulated the war due to unopposable American bombardment from sea and air and the use of the atomic bomb on two of her cities.

One of the largest factors in Japan's inability to continue the war was the enormous destruction which the American fleet wrought upon her shipping. To this last, the Bergall contributed two AK's (cargo), one AO (tanker), One CA (heavy cruiser), and possibly another AO. She had damaged a battleship, a heavy cruiser (aircraft reconnaissance showed that on the night of 13 December, 1944 the Bergall had not been pursued because one of her salvos had hit the second ship) and two oilers. She had also sunk about a dozen minor craft: patrol boats, tugs, barges, junks, all that the Japanese had to offer in the last months of the war. She was one of the submarines selected to remain in commission through the peace, and on 15 September, 1946 was undergoing overhaul in the Portsmouth Navy Yard waiting to return to the ocean which she had helped make Pacific.

(From personal accounts by shipmates)