On recommendation, we did a few dives at Dos Ojos (huge caverns) with Cenote Dive Centre (google them). We'd heard from other people we met how they had bad experiences with well known Mexican-run companies, but Dave (Canadian Owner) has 20 years in the business and the experience was much personal, as opposed to being in a huge group. The two dives we did were similar, with huge formations, a bat cave and tiny fish. It was a cool experience, but like ice diving, it's a one-off thing for us. We prefer open-water dives.
After lunch we headed to Akamul, for free snorkelling. We snorkelled around half moon bay (with only us in the lagoon), which was filled with loads of varieties of hard and soft coral and a few fish. The next bay along (behind the dive shop), we snorkelled for a couple of hours with 7 sea turtles (including a baby one), rays and squid. We loved it. The best things in life are free ;-).
We decided to camp near Tulum along the beach. However, Dougal got stuck in the sand, but after 30 minutes of 10 Mexican men pushing and a pick-up towing us out, he was free. Completely blame Gwyn on this one. He made up for it by doing a wicked BBQ on the beach, 4 metres away from sea, watching the lightening in the distance over the Caribbean sea.