In the Pacific, with Japan viewed as the major threat to American security, naval and military planners began building up the defenses of Hawaii and other possessions.

After repairs at the Philadelphia Navy Yard from 12 April-14 May followed by two weeks of liberty at New York, the tender then escorted submarines R-11, R-12, R-13, and R-14 from New London to the Panama Canal from 3–27 June.

Over the next six months, the tender's crew helped improve the submarine base at Cavite and supported local operations by the division's diesel boats.

One officer on the survey team, Lieutenant Commander Sherwood Picking from the Aeronautical Test Laboratory in Washington, D.C., later wrote, from "a strategic point of view, Wake Island could not be better located, dividing as it does with Midway, the passage from Honolulu to Guam into almost exact thirds."

The convoy stopped at Magdalena Bay and Acapulco in Mexico and at Corinto, Nicaragua, before mooring at Coco Solo in the Canal Zone on 28 August.

In mid-August, after a stop at Vancouver, British Columbia, the squadron visited Astoria, Oregon, to look over a site contemplated for another submarine base.

On 2 January 1924, Beaver, in company with ten submarines of SubDivs 16 and 17, steamed south from San Pedro for another fleet exercise in the West Indies.

The following month, after turning over the flag of Pacific Submarines to Savannah, Beaver sailed for the Philippines with six S-boats of SubDiv 16, arriving at Manila on 12 July.

In the fall and winter, as the monsoons moved southwest toward French Indochina and the Dutch East Indies, the tender and her charges shifted back to the Philippines for operations out of Cavite.

For the next seven years, Beaver remained in Hawaiian waters, tending submarines during local operations and steaming occasionally to Wake Island, Midway, and French Frigate Shoals for deployment exercises.

Intended to improve her capability to support submarines overseas, Beaver's modernization also included the installation of new repair equipment and the latest communications gear.

The tender sailed for the east coast in November 1940, passing through the Panama Canal and arriving at her new home port of New London, Connecticut, at the end of that month.

The agreement, which transferred 50 "overage" destroyers to the Royal Navy in exchange for 99-year leases on bases in the Western Hemisphere, allowed American forces to move into particularly important islands in the West Indies.

For the next nine months, the tender alternated between Bermuda and New London, supporting submarine patrols along the Caribbean-Bermuda-New England shipping lanes and assisting antisubmarine training for American destroyers.

On 3 September 1942, Beaver and six submarines formed SubRon 50 at New London, a special unit intended for Operation "Torch" – the planned November landings in French North Africa.

In October, while five of her submarines sailed with Task Group 34.11 (TG 34.11) for operations off North Africa, Beaver joined convoy HX 212, bound for the United Kingdom.

Although the convoy escorts – including the Coast Guard cutter Campbell and three British Commonwealth corvettes – drove off most of the attackers, three merchant ships were sunk and another two damaged by U-boats that broke through the defensive screen.

Starting in April, they patrolled off Norway, Iceland, and then the mid-Atlantic, searching for enemy U-boats and waiting in case the German surface fleet broke out from its Scandinavian bases.

Needed to support the growing American submarine offensive in the Pacific, the tender got underway 10 days later for San Diego, via the Panama Canal.

Assigned to SubRon 45 at Dutch Harbor, Beaver furnished tender services to North Pacific Force submarines when they returned from patrols in the northern Kurils and the Sea of Okhotsk.

She then returned to the west coast, anchoring in Puget Sound, in the state of Washington.I served aboard the Beaver during her voyage through the Pacific, to Okinawa, Japan and China.