We found the Sebago Watersports booth around the 600 block of Duval. During Spring Break, this booth was open all day and till midnight every night. The guys who work there are constantly recruiting people to go on the Sebago trips. They will throw out all kinds of sales tactics to get you to go on their boat.... They'll tell you they are giving you the best deal and that there's only a few spots left and the boat is filling up quickly, and of course flattery is used too ("all the guys will be hitting on you"). The night we happened to stop by, a well-tanned, friendly guy was working there (Dave). Dave first told us that the combination sail/snorkel was $45. I knew we could do better, and I told him, and he immediately dropped the price to $35. With the promise of a good crowd, free drinks, and a large boat, we signed up for a sail two days later.
On the day of our sail, we arrived an hour before our departure time, as requested. This hour was used to check in, board the boat, get our snorkeling equipment, learn the rules, and get a quick picture taken of our group. Some words of advice: get there on time to get checked in so you can be one of the first people on the boat, so you can get a seat and a table. The free "drinks" included draft domestic beer, wine, soft drinks, and water. Mixed drinks, bottled beers, and "premium" wines cost $4-$5. None of the alcoholic beverages would be available until after the snorkeling. The boat was a huge, fairly new catamaran, with a large covered area with tables and benches and the bar, and a deck around the outside of the covered area. On our particular sail (Weds from 1:30 to 4:30), the boat was filled primarily with college-aged girls, a few guys, and a few families.
It took about 45 minutes to get to where we would snorkel. Beforehand, we had a quick lesson on snorkeling with the provided equipment (mask, snorkel, flippers, and inflatable "buoyancy" vest), and how to get off/on the boat. At the snorkeling sight, we were allowed to snorkel for about an hour. The hour flew by as we saw many types of coral, underwater caverns, many very colorful tropical fish, and all kinds of neat stuff. The coral reef is very close (3 feet) to the top of the water in some places, so we had to be careful not to touch it.
Once back on the boat, we just relaxed. We were too exhausted to even drink beer. After we got back, the pictures they had taken were available for $10, with extra copies for $5. We all bought one... we couldn't resist. The other three girls in my group also bought Sebago t-shirts for $14 each.
Sebago also offers parasailing and some other stuff. Go to their website @ http://www.sebagocatamarans.com/.