Debbie, the snuba adventure I booked online with www.visnuba.com
. I talked with a girl named Tami, very nice. You can book it but they don't charge your credit card. You pay for it that day and you can choose cash or credit card.
For the Dolphin encounter in St. Maarten, the excusrsion takes place in Anguilla, there is a compnay called www.shoretrips.com
, his name is Barry, his contact number is on the website and he is stateside(Wisconsin). It's kinda of pricey, but includes the ferry, trip to the beach, lunch, beach/snorkel equipment, and then the Dolphin Encounter.
Hope this helps, Paul