We booked this very last minute, and its a very family friendly tour, which wasn't our favorite since we were travelling without kids and prefer adult-only activities. But I can't ding Sebago for that, it was very clear before we booked that it was a family environment. And they did have plenty of free beer and wine, which eventually makes up for a multitude of screaming children's sins.
They took us out 7 miles to a lighthouse and reef in the Atlantic. Beautiful spot and we got to see a 6 foot black-tipped reef shark during our time in the water, among lots of other reef fish.
The captain and crew did a fabulous job getting everyone - including the majority of those on board who were clearly not familiar with boats, the ocean, or snorkeling - set up and into and then out of the water. And they did a similarly great job pouring wine and beer on the trip back to Key West.
We will opt for a more experienced snorkeler and adult-oriented cruise next time, but if you're new to the ocean or travelling with kids, this is a can't miss activity for you.