Nice trip, but the focus was not snorkelling. At least, on the trip I was on, the focus and time was really on sightseeing and drinking.
The crew were nice, the boat had a fun atmosphere, but we only had two short snorkels in a 4 hour trip :
1. Appx 20 minute drift swim - which was great.
2.Blue Bay "marine park" . Again it maybe lasted 20-30 minutes,
At Blue bay, there was a scrum of boats all many with swimmers jumping off the roofs of their boats. The water was murky and, but for the copious amount of fish food being dumped, I think the place would have been a ghost-town due to the noise. I believe people do see turtles there, but can only say that the turtles must not be of a nervous disposition.
So a 4 hour tour with appx 1 hour of snorkelling. The rest of the time was either watching the glass bottom boat trim the Coral, or having lunch or snacks in two other locations.
I realise that this may read as a negative review. It's not really, it's that I was expecting something different.
I found something that matched my expectations two weeks later on La Digue, Seychelles with Nevis Ernesta La Digue Boat Excursions.