Scubapro Vent 2 Purge Valve Scuba Diving Snorkel

A classic open-top snorkel is a simple tube, the most reliable design, but it takes on water when a wave passes or you duck under. A semi-dry snorkel adds a splash guard at the top that deflects surface chop, though it still floods if fully submerged. A dry snorkel adds a float-operated valve that closes the top when submerged and keeps the tube mostly dry, at the cost of more moving parts and a little extra bulk and buoyancy.

A purge valve is a one-way valve in a sump below the mouthpiece that lets water you blow out drain away instead of sitting in the tube. It makes clearing easier, since a short sharp breath clears the snorkel with much less effort. The tradeoff is one more part that can foul with sand or grit, so rinse it and check that it seats cleanly.

Snorkels attach on the left side of the mask with a keeper that grips the mask strap, leaving your right side clear for the regulator hose. Position it so the mouthpiece reaches your mouth with the tube running alongside your head, without twisting the strap or pulling the mask skirt off its seal. Many keepers are quick-release, so you can remove the snorkel without disassembling the mask.

It depends on your training agency, the dive operation, and the diving you do, since some courses and operators require one. A snorkel lets you breathe at the surface without using tank gas, which matters on a long surface swim or in chop while waiting for the boat. Follow your instructor's or operator's requirements, and consider a folding snorkel if you want one stowed rather than on your mask.

A snorkel that is too long or too wide increases the volume of air you rebreathe and makes clearing harder, which is why recreational snorkels cluster around similar lengths and bore sizes. A flexible lower section lets the mouthpiece drop away from your face while you are breathing from the regulator. Mouthpiece comfort matters more than any other feature, so pick one you can hold without jaw fatigue.

Rinse the tube, mouthpiece, and purge valve in fresh water after each dive day, then let it drain and dry fully, because standing salt water in the sump grows mold. Check the mouthpiece for splits and the purge valve for trapped grit, both of which are inexpensive to replace. Store it out of direct sun so the silicone stays soft and clear.