What the rate quote glosses over: all-inclusive means something looser in Cozumel than on the mainland, so read the fine print. On most properties the rate covers your room, meals, snacks, and drinks, sometimes a buffet plus a sit-down restaurant or two. Where it splits is diving. Some dive resorts fold a set number of dives, tanks, and weights into the package; others keep diving separate and run it through the on-site shop, which means a low room rate can climb fast once you add your tanks. Before you commit, pin down four things: whether diving is included or extra and how many dives you get, whether you arrive by airport transfer or by car ferry from Playa del Carmen and who arranges it, which strip of the island the resort sits on and how far that is from town and the dive sites, and whether the place is family-friendly or genuinely adults-only. Sorting that out up front is the difference between a package that fits and one that ambushes you at checkout. Not staying all-inclusive? A beach club day pass gets you the sand-and-pool day without the room package.