USCGC Thunder Bay (WTGB-108) is the eighth vessel of the Bay-class tugboat built in 1985 and operated by the United States Coast Guard.

She is homeported in Rockland, Maine The 140-foot (43 m) Bay-class tugboats are operated primarily for domestic ice breaking duties.

They are named after American Bays and are stationed mainly in the northeast United States and the Great Lakes.

On 4 February 2021, Thunder Bay conducted a icebreaking mission at the Penobscot River.

[2] On 18 June, the ship finished the In-Service Vessel Sustainment program and departed Coast Guard Yard in Curtis Bay, Maryland.