Using Your Snorkel
Breathing Through Your Snorkel
You'll breathe through your snorkel while surface swimming. This allows you to view the area below you without lifting your head out of the water.
Water can enter the snorkel when waves pass overhead or another diver splashes water in your area. To avoid inhaling water, use your tongue as a splash guard by placing it against the roof of your mouth. This will warn you of water entering your mouth before you inhale it.
The snorkel's diameter and length creates some breathing resistance as you inhale and exhale. While this should not adversely affect your breathing under normal situations, it may be difficult to breathe through the snorkel if you exert yourself. For this reason, you should relax and breathe slowly when using the snorkel.
Clearing Your Snorkel
Your snorkel will fill with water when you dive below the surface, so you'll need to clear it once you surface by using one of two methods.
The blast clear is the most popular method. This involves blowing out through the snorkel to force the water out through the top. If your snorkel has a purge valve, water will also exit through the purge valve below the mouthpiece.
Another method, called the displacement clear, can be used with snorkels not equipped with a purge valve. The displacement clear begins while you are still underwater. As you begin to surface, look straight up and exhale a small amount of air into the snorkel. As you ascend, the air will expand and displace the water. By the time you reach the surface, most if not all of the water will be cleared from the snorkel.