Cozumel is a Caribbean island just off the Yucatan Peninsula in southeastern Mexico. It has great beaches and safe nice people, but is a little expensive.
Generally, everything good to see in Cozumel is underwater. Snorkeling options are fairly limited due to boat traffic, but scuba divers can explore beautiful reefs via boat or shore dives for a relatively small equipment rental fee.
Attractions in Cozumel:
SCUBA diving — Cozumel is one of the premiere scuba diving destinations in the Western Hemisphere. The island abounds with dive shops, most willing to give you a pseudo-resort certification and take you out, but for an added price. A certified dive (two tanks) will set you back around $60. Most dive locations are located well south of the city proper, as are the best dive shops if you want a short boat ride.
Aqua Safari— training, certification and two types of daily dive trips (fast or slow boat). Good company but they tend to pack more people on a dive trip.
Snorkeling — logically enough, is the second most popular activity. Many beach-side dive shops rent equipment for $7-10, though many beaches are private and require pay to enter.
Beach lounging — most of Cozumel has rough rocky beaches not suitable for swimming or sun bathing. The areas that are suitable have been turned into small parks. Entrace fees are small, around $10 / couple, which includes a beach chair and umbrella as well as access to the washroom and shower facilities. Playa San Francisco is located 20 minutes by taxi south of town and has a restaurant on site.