Many of Treasure Island’s outdoor activities naturally revolve around the ocean. Along the coastline are numerous small businesses that offer snorkeling and diving, chartered boating and fishing and dolphin and manatee cruises.

There are many small companies that offer snorkeling and diving instruction as well as equipment rentals, including Treasure Island Diving. Divers who wish to interact with manatees can charter boats for semi-guided tours.

Fishing and boating are both incredibly popular activities for Treasure Island vacationers. Some prefer to take scenic cruises through the tropical waters courtesy of the many charter companies in the area, like Mega-Bite Charters. Deep sea anglers, on the other hand, have an opportunity to reel in barracuda, tarpon, blackfin tuna, Mangrove snapper, grouper, amberjack, Spanish mackerel, kingfish on a deep sea charter, such as Jubilee and Treasure Island Deep Sea Fishing.

The Gulf of Mexico is full of sea life including both dolphins and manatees. There are many guided tours designed to take visitors up close and personal with these beautiful creatures. The Pirate Ship at St. John's Pass is a favorite with families, offering an afternoon of siteseeing and adventure on a pirate ship, while Discover Florida Tours specializes in seeking out dolphins, manatees and other maritime wildlife.

For bicycling enthusiasts, the best spot in the Treasure Island area is the 34-mile-long Pinellas Trail, which stretches from St. Petersburg to Tarpon Springs. While also ideal for joggers, skaters and walkers, the trail winds along an abandoned railroad corridor which has been converted to a lush and scenic green space with tidal streams and Spanish moss-draped oaks. The trail features bike racks and places to stop for refreshments. It is open every day during daylight and pets are permitted, but must be kept on a six-foot leash.