A wide, less-crowded beach at kilometre 13 of Boulevard Kukulcán, between two large hotels but with a public access point easily found from the bus. The sand is fine, the water turquoise and clear, and (because the entrance is hidden) the crowds are much lighter than at Playa Tortugas or Caracol.
There are no big palapa restaurants directly behind, so bring water and snacks or walk five minutes to the hotels for food. Currents can be stronger here than on the calm north-side beaches — pay attention to lifeguard flags. The R1 bus drops you at the entrance.