The island has a volunteer fire department, gold course, and a marina. There are little to no vehicles on the island, even though there are roads. Travel is mostly done by foot or on golf carts. There is also a community store with key items such as supplies and groceries.
According to the United States Census Bureau, the CDP has a total area of 0.692 square miles (1.79 km²), of which, 0.688 square miles (1.78 km²) of it is land and 0.004 square miles (0.01 km²) of it (0.58%) is water.
Hat Island is located at 48°0′48″N 122°19′14″W (48.013340, -122.320562).
Hat Island is located in the Puget Sound, in a branch called Possession Sound. To the west is Whidbey Island and the community of Langley. North is Port Susan, Camano Island and the Tulalip on the Snohomish County mainland. East is Jetty Island and Everett. South is Everett and Mukilteo with Clinton is to the southwest on Whidbey Island.
There is a monthly newsletter with community events distributed online for residents of the island. The island community has a very active online website with the latest information.
There is currently one walk-on ferry named the Hat Express which transports walk-on passengers to and from the island. The maximum capacity of the ferry is 88 passengers. It runs a limited schedule on Thursdays, Friday evenings, and weekends between the Everett Yacht Club on the west end of 13th Street in Everett, and the Hat Island Marina. Runs vary depending on the season.