Attached to the Atlantic Submarine Flotilla, G-1 spent the next year and a half conducting dive training and torpedo firing exercises in Long Island Sound and Narragansett Bay.

In company with sister ship G-2, tender Fulton and tug Sonoma, G-1 sailed south on 25 March into Chesapeake Bay and down the seaboard for Norfolk, Virginia.

On 2 April, while off Old Point Comfort, G-1 grazed steam ship Ocean View, wrecking the submersible's wooden false bow.

Heavy seas encountered during this coastwise passage caused the two G-class submarines to roll heavily, spring oil leaks, and pop engine rivets.

Following a three-week yard period in Charleston, the two boats – accompanied by Fulton and gunboat Castine – proceeded back to New York City on 6 May, arriving there three days later.

Upon arrival, retired Rear Admiral Yates Stirling Jr., senior aide on the staff of Commander, Submarine Flotilla, Atlantic Fleet, inspected the boat and concluded the G-boats were crude and inefficient in comparison to current designs.

Aside from minor repairs at New York in June, this duty continued until 3 October, when she set course – along with tender Ozark – for a training cruise to Chesapeake Bay.

Concurrently, given the entry of the United States into World War I, G-1 tested submarine nets and detector devices for the Experiment Board.

With German U-boats reported off the coast in June 1918, the submarine spent two four-day periscope and listening patrols off Nantucket, Massachusetts, as a defense screen for shipping.