The 3 Islands Tour is offered as halfday or fullday
2-4 snorkeling stops around the islands (exact locations can variate due to weather and sea conditions). Coco Island, Big Sister Island, Small Sister Island, Felicite. Sometimes even Ave Maria is on the list -> known as a diving spot, but also nice for snorkeling.
If you are lucky you can swim with a sea turtle. You may also find small reef sharks, rays, batfish, parrotfish, surgeonfish and many more. Most of the corrals have been destroyed/bleached due to El Nino & Tsunami, but its nice to see that is slowly recovers.
The extra: normally one of the crew members will join you in the water and make sure you wont miss anything you might not have seen without them. Another crew member will stay on the boat to ensure your safety.