If you arrive in Cozumel early in the morning you can rent scooters and
spend a couple of hours taking a ride around the south side of the
island. Lots of deserted white beaches with beautiful waves crashing in.
Early in the morning you will be virtually the only humans on this part
of the island. You can stop and walk on a couple of the beaches, maybe
have a beer at one of the little bars that are just opening for the day
and still be back in town in time to go snorkelling at Chankanaab, which
is exactly what we did.

Tom Hudson