Snorkeling in Roatan is excellent and there are a lot of places to go. I really like the Half Moon Bay Inn on the West end of Roatan. Great dining, great snorkeling and overall a great experience. It is within easy walking distance to the West End and a good number of restaurants, shopping and other attractions.
When I went to Roatan I did a tour on a 62ft wooden yahct. They first took us for a sail around the island, then to a spot for snokeling. It was over a coral reef. It was beautiful. I remember getting my back sunburned from snorkeling. After they took us to a restaurant for lunch. If someting like that is still available you might enjoy it.