but when we have done snorkel tours in the past on other cruises the disinfectant was throwing them in a cold bucket of sea water and then rinsing with fresh water. It was gross enough to watch them do that but then they handed them out to people on the boat and they took them! It was then that I swore off renting and bought my own. A year later we took up scuba so I for sure wanted my own but now you can get the mask and snorkel for so cheap that I dont think it is worth it to rent! The other benefit of owning is that you are SURE your mask fits right. There is nothing worse than getting all ready to snorkel and finding out your rented mask leaks because it doesnt fit your face! If it were me I wouldnt EVER rent another mask because of cleanliness and fit! We saw that mask cleaning ritual using sea water and fresh water (both COLD) happen in Cozumel and Grand Cayman at 2 different places on 2 different cruise lines with 2 different independent tour operators!
Hope this helps!
Heidi