I have night dived in several locations in Cozumel, depending on the dive charter or groupyou go with, some only have preferences to the easiest locations, however, you may ask the shop you are diving with as to what they feel is within your abilities, Chan Kanaab, Tormentos, Yucab wall, San Fransisco, Gardens, all are good spots to night dive, some of the shops do not like to go to these places because of the distances,.....lots of octopus and shrimps, as well as the corals blooming at night...where ever you go, remember to respect the creatures that are "sleeping" and keep your distance from the corals that are open....enjoy....