Shell Island is an undeveloped barrier island sitting across the inlet from St. Andrews State Park, accessible only by boat. There are no facilities, no vendors, and no cars — just seven miles of white beach and dune scrub. Small ferries run from the state park marina and from various outfitters along the main strip.
The snorkeling off the southern tip is the best in the area — the water runs shallow over seagrass and the visibility is usually good enough to see sea turtles and rays. Dolphins are a regular presence in the channel between the island and the mainland; kayakers often find them approaching curiously. The exposed, west-facing beach catches the strongest surf, while the lagoon side is flat and warm and good for wading with children.