On the main street through Puerto Morelos village, five minutes from the pier the boats leave from, open seven in the morning until seven at night.
The reef here sits closer to shore than almost anywhere else on the coast — a few hundred metres out — and the whole stretch has been a national marine park since 1998, which is why it is in noticeably better condition than the reef further south. They also run the cenotes inland and keep a second shop in Cancún, on Sayil near the bullring.