We did a 8pm Manta Ray snorkel tour. It was AMAZING!! We went on a 20 minute ride to the cove near the airport. After five minutes six rays were swimming below us. They stayed the entire time we were in the water (30 plus minutes) feeding off the plankton attracted by our light board. The largest ray had a 14 foot wingspan! They swam and rolled within inches of us - sometimes brushing into us. When we got back on board, we were greeted with hot soup and fruit. Captain Tim and his crewman and Cindy, who met with wetsuits, were all very friendly. I would recommend wearing a wetsuit since the water was chilly at night.