Located in the sprawling Colt State Park, Bristol Town Beach (401/253-7482, www.riparks.com ) is the most accessible beach in the East Bay , but tends to be somewhat rocky and crowded in the summer.
The Audubon Society of Rhode Island (1401 Hope St./Rte. 114, Bristol, 401/245-7500, www.asri.org ) runs an excellent environmental center and wildlife preserve on the bay coast. Along with nature exhibits (including a 33-foot-long whale model), it maintains boardwalks and paths to nearby marshes.
The 15-mile East Bay Bike Path (www.riparks.com ) offers beautiful views of the bay as it meanders from East Providence  to Bristol . Bikes can be rented from Your Bike Shop (51 Cole St., Warren, 401/245-9755).
Cygnus Sailing Adventures (401/413-8109, www.sailcygnus.com ) offers narrated sails in Bristol harbor on the gaff-rigged sloop Cygnus. The East Bay Sailing Foundation (Bristol Yacht Club, Poppasquash Rd., Bristol, 401/253-0775, www.bristolyc.com ) offers sailing instruction in 15-foot Mercurys.
Bay Queen Cruises (461 Water St., Bristol, 401/245-1350, www.bayqueen.com ) provides narrated tours of the bay on a 114-foot cruise boat. Ocean State Adventures (99 Poppasquash Rd., Bristol, 401/254-4000, www.kayakri.com ) rents out sea kayaks as well as leading nature tours and moonlight paddles in the bay.