There are several independent companies offering tours of Roatan. There are also several major shore excursions companies that offer tours as well.
We much prefer this way to book excursions than booking through the cruise line - much easier, cheaper, and a whole lot less crowded and regimented making for a more enjoyable experience.
With that said, West Bay Beach has some of the best snorkeling I've ever seen around the world. So if you're into snorkeling or scuba diving, try it there as it's awesome!
47 Cruises & Counting! Favorites: Paul Gauguin to Tahiti: Uniworld River Cruises in Europe; any of the Celebrity Solstice-class ships; Holland America for 12-nights in the Baltics & Russia; RCCL for 14-night Greek Isles, Turkey, & Croatia; Holland America for 14-day Alaska cruisetour; 10-night Canada/New England cruise; 21 days in Hawaii including a 7-night NCL cruise; Oceania for 25 days in Asia; & 3 months touring Europe by train. And many days spent in all-inclusive resorts!