Be sure to dive the "Christo". I think it's off of Palancar reef, but can't remember. Big statue of Jesus with arms stretched. Sort like the one on the hill in Brazil.
Right off the beach where the old cruise ship dock is(maybe was) there's a sunken airplane. Has a 'cuda that claims it as home but will let you snorkel around it.
Beach divable underwater park that you can do in about 20 feet of water.
Very fun dive vacation.