Hat Island may refer to:
Sombrero, Anguilla (also known as "Hat Island"), the northernmost island of the Lesser Antilles Gedney Island (Washington) (also known as "Hat Island"), an island in Possession Sound, part of Puget Sound, Washington, US Hat Island, Washington, a census-designated place in Snohomish County that is coterminous with Gedney Island Hat Island (Lake Michigan), located in eastern St. James Township, Charlevoix County, Michigan, US Hat Island (Wisconsin), located in the Town of Gibraltar, Door County, Wisconsin, US Putulik formerly Hat Island, in the Kitikmeot Region, Nunavut, Canada Hat Island (Sverdrup Islands), in the Qikiqtaaluk Region, Nunavut, Canada Cocked Hat Island, Nunavut, Canada Vatu Vara, Fiji Eretoka Island, Vanuatu Hat Island (Bay of Islands), New Zealand Motupapa Island (Cocked Hat Island)