It's such an incredible place. I already want to visit again.
I'm not exactly sure of the water temp, but I read online that it's about 20°C. Such a welcome relief from the Mexican heat! I believe that most of the scuba divers wear wetsuits when diving there.
Oh oke, Its enough to swim without any gear. Assuming temperature does not get colder deeper :D
Oh yeah it's absolutely fine for swimming and snorkelling without gear. It's actually really nice. But as you say, not sure about the deeper dives. Some of the footage from various cenote dives looks so epic. I'd love to give it a go some day. Scares me a little though. I'll just work on my snorkelling skills for now and work my way up 😂