Sombrero Beach

Sombrero Beach is Marathon's primary shore-accessible snorkeling site, located along a public beach in the Florida Keys. A small reef system sits roughly 100 yards offshore, reachable by an easy swim from a sandy beach entry. The site is free to enter, with restrooms, picnic areas, and parking available on site.

The reef runs shallow, with water depths ranging from 3 to 15 feet (roughly 1 to 4.5 metres), making it well suited to beginners, children, and anyone looking to snorkel without the structure of a guided boat trip. Small coral formations and seagrass beds make up the bottom terrain. The reef area is smaller than offshore alternatives and holds less marine life than deeper sites, but supports an active, accessible ecosystem. Swimming past the buoys reaches the better snorkeling, and the rock jetties at each end of the beach are also worth checking for fish.

Common sightings include parrotfish, sergeant majors, and rays, with young fish drawn in by the coral formations and seagrass beds. Sombrero Beach is a designated sea turtle nesting beach, so seasonal restrictions may apply; visit with that in mind and keep clear of nesting areas.