Peto recommissioned, completed fitting out and shakedown, transited the Panama Canal, and arrived at Brisbane, Australia, on 14 March 1943.

That night she proceeded toward the equator to cover the Truk-Kavieng shipping route, arriving on station the next day.

On 5 May, she made a night attack conducted by sound and radar alone, firing three torpedoes at a target for one possible hit.

The depth charge missed by a wide margin, and Peto submerged to 200 feet (61 m) and avoided damage.

[7] Peto moved to the Truk-Kavieng-Rabaul traffic routes on 20 September, and two days later, sighted five escorted ships headed toward Rabaul.

While Peto attempted to close for a night attack, an alert escort only 7,000 yd (6,400 m) away detected her.

On 9 December, while firing on a ship in a convoy, her target apparently saw the torpedoes coming and turned toward them to avoid being hit.

Boang Island On 19 December Peto under Commander Nelson received orders to return to Tulagi.

On Christmas Day a reconnaissance team of ten US specialists an Australian Coastwatcher (Captain H. Murray) his Sergeant (Bill Dolby) and their four native scouts were embarked.

Returning to Tulagi Commander Nelson made Captain Murray an honorary member of the US Submarine Service.

In return the team presented the "Peto" with a Japanese machine gun they had captured during the ambush.

The target was immediately engulfed in black smoke and her crew heard depth charges in the distance.

On 28 April 1944, Peto, along with the submarine USS Perch (SS-313) and an escorting surface warship, departed Pearl Harbor for her patrol area south of Formosa.

She made only six ship contacts during the entire patrol and couldn't obtain a favorable attack position on any of them due to Japanese aircraft in the vicinity or shallow water.

On 21 June 1944, Peto headed for San Francisco, California, for major alterations at the Bethlehem Steel Company shipyards.

A burning ship with hull down was seen to the east and it was assumed the submarine USS Barb (SS-220), which was also in the vicinity, had connected.

The torpedoes fired from the bow tubes struck home as the leading ship, Tatsuaki Maru, blew up and promptly sank.

Peto came around for a coup de grace but saw that it was unnecessary, as only the stern of Aisakasan Maru was above the water, still burning like an inferno.

On 24 July, she rescued two pilots from the aircraft carrier USS Lexington (CV-16), one with gunshot wounds in both legs.

On 10 August she picked up a Royal Navy Fleet Air Arm pilot from the aircraft carrier HMS Formidable.

On 15 August 1945, she was assigned a life guard station to cover air strikes on the Japanese Home Islands, but hostilities with Japan ceased that day.

This article incorporates text from the public domain Dictionary of American Naval Fighting Ships.