There’s not a rock in sight at Rocky Neck State Park (244 W. Main St., 860/739-5471, www.ct.gov/dep , $9 in-state-registered vehicle or $14 out-of-state-registered vehicle weekends, $7 in-state or $10 out-of-state weekdays) outside of Old Lyme —just miles of white sand beach fronting Long Island Sound. The beach is a popular one with families.
Other good swimming spots in the area include Esker Point State Park (Eastern Point Beach, Groton, 860/536-5680, $10 weekday parking, $20 weekend parking), a 600-foot stretch of sand with picnic facilities and snack bar; and the picturesque DuBois Beach (Water St., Stonington, 877/286-9784), which offers nice views of Stonington Harbor and shallow depths for swimming. The latter fills up quickly, so arrive early to snag a day-use permit.
Behind the Denison Homestead Museum, the Denison Pequotsepos Nature Center (109 Pequotsepos Rd., 860/536-1216, www.dpnc.org , 9 a.m.–5 p.m. Mon.–Sat. and 10 a.m.–4 p.m. Sun. year-round, $6 adults, $4 seniors and children under 12) offers eight miles of gentle trails in its 300-acre nature preserve. Several species of hawks and owls hang out in flight enclosures on the grounds.
Located just outside New London , the Sunbeam Fleet (15 First St., Waterford, 860/437-3699, www.sunbeamfleet.com , $40 adults, $37 seniors, $25 children under 12, plus $5 pole rental) has three boats of various sizes for deep-sea fishing charters. Two-to-three-day trips go out in search of tuna, shark, marlin, and swordfish. The fleet also runs lighthouse cruises and seal-spotting expeditions.
The 1967 windjammer Mystic Whaler (860/535-1556, www.mysticwhalercruises.com ) sails from her home port of Mystic  for multi-day cruises in search of whales, lighthouses, and moonlit nights. Ports of call include Block Island , Newport , Shelter Island , and New York City . The ship is also available for day sails on select dates.