Just returned Sat. from our second fantastic trip to the Coral Mariem. As was mentioned, dress for the buffet and Mexican rest. are casual. Nice shorts and a shirt with short sleeves are fine for men.
Try the quad (funny bike) tour. There is a man named Pedro who walkes around the pool selling this tour. It's three hours of riding through small villages and sugar cane fields down to the ocean and back. Covers about thirty miles. It's a lot of fun and you get a chance to see things off the beaten path.
John