Taninul is the warm spring country west of Tamuín, often paired with Tamtoc on local day tours. The water comes from the cave system at the foot of the Abra-Tanchipa hills and is used for bathing in a tropical, sulphurous setting.
It is not a wild swimming hole, and some facilities are tied to the long-running spa hotel, but after a hot morning on exposed archaeological sites it makes practical sense.