Ocean Sports (77 Ave. Isla Verde, 787/268-2329, www.osdivers.com , Mon.–Sat. 10 a.m.–7 p.m.) rents and sells snorkel and scuba equipment from its two stores and operates scuba and snorkel tours from Fajardo . Road transportation to and from San Juan  is available.
Caribbean School of Aquatics (1 Calle Taft, 787/728-6606 or 787/383-5700, greg [at] saildiveparty [dot] com, www.saildiveparty.com ) offers full- and half-day sail, scuba, snorkel, and fishing trips from San Juan and Fajardo on a luxury catamaran with Captain Greg Korwek. Snorkel trips start at $79 per person; scuba trips start at $139 per person.
Scuba Dogs (D-13 Buen Samaritano Gardenville, Guaynabo, 787/783-6377, www.scubadogs.net ) provides scuba and snorkeling trips all around the island for everyone from first-timers to those seeking PADI dive training. It also sells and rents equipment.
Caribe Aquatic Adventures (Hotel Normandie, 499 W. Ave. Muñoz Rivera, 787/281-8858 or 787/724-1882, www.diveguide.com/p2046.htm ) offers snorkel and reef dives four times daily, as well as light-tackle and deep-sea fishing trips.