She encountered six destroyers, three freighters and a patrol boat, attacking none, before calling at Dutch Harbor on 8 August en route back to Hawaii.

Roy S. Benson assumed command before Trigger began her second war patrol, conducted from 23 September to 8 November in "Empire Waters" (the seas immediately surrounding Japan).

Enemy shells soon began exploding close to Trigger, and the 4,000 ton ship turned and accelerated in an attempt to ram the submarine.

Trigger launched three torpedoes "down the throat" at the onrushing destroyer and, one minute later, observed an explosion so powerful it threw enough flame and water into the air to obscure the target.

When the air cleared, the enemy ship was still intact, suggesting Trigger's first torpedo may have exploded prematurely, detonating the next two by its turbulence.

Near midnight of 20 October, Trigger fired a spread of four torpedoes from very close range, 900 yards (820 m), in a surface attack on a 10,000-ton tanker.

From 3 December 1942 to 22 January 1943, the submarine conducted a combined minelaying and offensive patrol, again in waters surrounding the Japanese home islands.

Trigger planted the northern half of the field and was working on the southern part when a cargo ship passed her, heading into the newly-laid mines.

Directed by an Ultra from Pearl Harbor, Trigger lay athwart the projected track of Admiral Koga's task force returning from Truk.

Although as she went deep the submarine heard four explosions, postwar accounting showed two of the torpedoes missed ahead and one failed to explode.

On 1 September, after a yard overhaul, Trigger (now in the charge of Commander Robert "Dusty" Dornin) was ready to begin her sixth war patrol.

She was patrolling some 30 miles (48 km) north of the Hoka Sho light when she sighted a convoy of three tankers and three freighters protected by Japanese planes.

Two hits started the victim down by the bow as the submarine's crew took turns at the periscope to watch Eizan Maru sink.

Trigger stood out to sea on New Year's Day 1944 to begin her eighth war patrol, this time in the Truk-Guam shipping lanes.

Two hits produced flames that reached mast height and several secondary explosions that marked the end of the 11,933-ton converted submarine tender Yasukuni Maru.

"Fritz" Harlfinger II, and still with "Ned" Beach as executive officer) headed for the Palau Islands on her ninth war patrol.

In the early morning of 8 April, she contacted a convoy of approximately 20 large ships with an estimated 25 escorts, and closed to attack.

Trigger ran at 300 feet (91 m) or more for 17 hours as six escorts dogged her trail and rained down numerous depth charges.

When the submarine surfaced, her forward torpedo room was flooded to her deck plates, and the hull air induction and most compartments were in about the same condition.

"[citation needed] Trigger met submarine USS Tang on 14 April and exchanged information by line gun.

The next day, Trigger's executive officer went on board Tang by a rubber boat, to borrow an air compressor part and to make plans for a coordinated search and attack.

On 18 April, Tang's executive officer delivered spare parts for the air compressor to Trigger, and she continued on patrol.

On 24 September, Trigger got underway to take station off the east coast of Formosa and perform life guard patrol for bomber strikes due on 12 October.

The morning of the strikes, she rescued a pilot from aircraft carrier USS Bunker Hill whose burning plane had crash-landed nearby.

Trigger rendezvoused with Salmon that night and was joined by USS Silversides and Sterlet to escort the damaged submarine to Saipan.

Trigger (with new skipper Commander David R. Connole) stood out to sea on 11 March to begin her 12th war patrol and headed for the Nansei Shoto area.

On 18 March, she attacked a convoy west of the islands, sinking the cargo ship Tsukushi Maru No.3 and damaging another.

She reported the attack on 20 March, and the submarine was subsequently ordered to radio as many movements of the convoy as possible to help find a safe passage through a known mined area of the East China Sea.

On 24 March, Trigger was ordered to begin patrolling west of the islands the next day, outside the 100-fathom (600 ft; 180 m) curve, and to steer clear of restricted areas.

The next day, Japanese planes and ships joined in a two-hour attack on a submarine heard by Silversides, Sea Dog, Hackleback, and Threadfin in adjacent areas.