Shelter Island is known as a destination for superyachts because it contains one of the few marinas in San Diego Bay with a deep enough harbor for these oversized vessels. The annual YachtFest, spotlighting superyachts, is held at Shelter Island Marina every September. The event also features mock gunbattles between two replicas of 19th century tall ships from the collection of the San Diego Maritime Museum.
The "island" is 1.2 miles (1.9 km) long and only a few hundred yards wide. A single street, Shelter Island Drive, runs the length of Shelter Island and also connects it to the mainland via a causeway lined with marine-related businesses.