Monday-Saturday at 1100 Captain Tama's Aquasportz Center, next to the Rarotonga Sailing Club on Muri Beach, offers lagoon cruises in a glass-bottom boat with a thatched sunroof with transfers, snorkeling gear, and a barbecue lunch included in the price. Before signing up, check with the folks in the Beach Hut at the nearby Pacific Resort whose glass-bottom snorkeling cruise may be cheaper. Captain Tama's rents windsurfers and snorkeling gear. Lessons in windsurfing are given. Equipment rental is possible every day.
The Big Kahuna Reef-Sub at Avatiu Harbor is a sort of glass-bottom boat with tiny jewelry case windows in an underwater viewing deck (it's not a real submarine). The 90-minute trips go out Monday-Saturday at 1000, 1200, and 1400 (no toilet onboard).