How long can you swim with a snorkel?
How long can you swim with a snorkel? With snorkel masks, you can descend up to six feet underwater without issue. However, your snorkel mask may fill up with CO2 and make it difficult to breathe. As a result, you shouldn't go deeper than six feet or even stay in the water for more than 25-30 minutes.
Why are full face snorkels not allowed?
CO2 can build up with these devices and put you in a very dangerous situation. There have been deaths, and many near death experiences. Can you breathe underwater with a full face snorkel mask? No, you can't breathe underwater with any snorkel.