Bahia Honda is an island in the lower Florida Keys.U.S. Route 1 (the Overseas Highway) crosses the key at approximately mile markers 36-38.5, between Ohio Key and Spanish Harbor Key 12 miles (19 km) west of Marathon, close to the west end of the Seven Mile Bridge.The island is virtually uninhabited, being home to 524-acre (2.1 km²) Bahia Honda State Park. Founded in 1961, the park occupies most of the island. The channel at the island's west end is one of the deepest natural channels in the Florida Keys.

The 2.5 mile natural, white sand beach was at one time named the best in the continental United States, making it popular for swimming. A nature trail near the park’s oceanside beach skirts a tidal lagoon before passing through a coastal hammock. Bicycling and inline skating can be done on the park’s 3.5 mile paved road, and there are several fishing and picnicking spots in the area.

Kayaks and snorkeling gear can be rented at the park, and boat trips for snorkeling on the reef are available. The park has a marina with boat slips available for overnight rental. Campsites and vacation cabins are available, although reservations for the winter months can be very difficult to get.The park is also a part of the Great Florida Birding Trail.