Some will say we've given a 'best kept secret' away. But the word is out: a cooperative from the tiny village San Antonio Mulix runs this gorgeous spot, consisting of two cenotes, 800m apart. Pay at the Centro Comunitario, then drive 2km along a dirt road. At the end of the road turn right to X-Batún or left to Dzonbakal.
X-Batún, although small, is one of the prettiest sinkholes around, its aquamarine waters open to the sky.
At the entrance to the 2km stretch is a community-run restaurant (mains M$40 to M$95), and you can stay in some simple Maya cabañas, complete with fans and mosquito nets (M$500 for four people).