During your first scuba-training session, you learned about clearing your mask. This foundational skill is essential to becoming a competent scuba diver. Mask clearing is the process of expelling water from inside your mask’s airspace the airspace into the surrounding environment without taking onboard any more water or — even more irritatingly — ingesting any water through your nose.

There are various circumstances when being able to clear your mask comfortably pays dividends. Under what circumstances might water leak into your mask — or might you want to let water into your mask — once it’s seated on your face? Here are a few of the most common.

A poorly fitting mask

If you’re diving in rental equipment, the chances are the mask is just a stock item from the dive center. Everyone’s face has a different shape. And, while a mask may be absolutely fine for someone else, it may not fit you.

Solution: A well-fitting dive mask should be one of the first things you buy as a new scuba diver. Visit your local dive shop to find one that works for you. If you are renting, try several masks for fit before committing to one for the dive.

An incorrectly seated mask

If it’s too high, low, tight or loose on your face, then your mask will leak, so ensure the mask is seated correctly on your face. Bring it to your face and — on this occasion only — inhale through your nose. If the mask sticks to your face when you inhale, slide the strap into place at the widest part of the back of your head. If not, readjust. Make sure the mask strap is neither too loose nor too tight since either extreme will cause leakage.

Solution: Take some time pre-dive to double-check your mask. Your mask should be on and correctly positioned when you confirm your readiness to enter the water.

Whisker worries

Male divers sometimes have problems with mask leakage due to facial hair — usually stubble — which leaves them with a steady dribble of water infiltrating their mask during the dive.

Solution: Maintain either a full beard or, ideally, remain clean-shaven. While some divers report vaseline on the top lip helps, a smooth face will work better.

Buddy banter

This is arguably the most common cause of mask leakage — during the dive your face shape changes, usually due to smiling or laughter. Consequently, water leaks into your mask, slowing oozing in the bottom with each chuckle.

Solution: Wear your best ‘poker face’ during the dive to maintain a smooth seal.

Bumping and banging

Objects appear larger underwater. This, combined with immersion in an unfamiliar environment, can lead to misjudgments of space or contact with other divers. Consequently, your mask can become dislodged mask. Either by self-infliction or a boisterous diver on a busy shot line, a bumped mask may temporarily break its seal and let in some water.

Solution: Be aware of your surroundings and leave a safe distance from other divers where possible.

Floppy fringe

Hair that has fallen inside your mask when initially seating it on your face will cause a leak. If hair can get inside the sealed skirt, so can water.

Solution: Sweep your hair out of the mask’s contact area. Be sure you’ve got an effective seal before entering the water.

Watch the fog

Incorrectly prepared and new masks have greater tendency to fog up, leaving you with compromised vision. You’ve got two options if this happens — either abort the dive or deliberately let a little water into your mask and clear it.

Solution: If you have a new mask, make sure you’ve properly prepared it before your trip and not straight from the box. Treat it with de-fog or spit before you jump in. Once you’ve done so, keep the mask on your face to maintain a seal from the outside world and prevent fogging before you submerge.

Clearing your mask: step by step

Many instructors immediately teach students how to clear a partially-flooded mask. However, if teaching this as a new skill or to hone the skill, it’s wise to first become comfortable with the concept that the mask is purely for the purpose of vision. Airway control and mask clearing are two processes intertwined.

Step 1: Master your airways

Airway control is the first skill to master: deliberately changing where you breathe in and out and breathing past small amounts of water. Stand in the shallow end of a swimming pool. Remove your mask and loop it over your left arm. While your head out of the water, put in your regulator and breathe in through your mouth and out through your nose. If you struggle, pinch your nostrils closed while inhaling through your mouth and release them as you exhale through the nose.

As you find a comfortable pattern, bend at the waist and put your face in the water. If you feel the urge to breathe in through your nose, hold your nostrils closed again with your right hand until you regain your natural breathing pattern, then release them and continue. Begin in small increments of five- to 10-second intervals of no-mask breathing and build up to approximately one minute without holding your nostrils.

When you’ve mastered Step 1, move unto Step 2 while beneath the surface and with the mask in place.

Step 2: Practice deliberately

Find a comfortable position underwater and begin by gently allowing water into your mask. You must do this smoothly, as a sudden rush of water can cause a reflexive urge to inhale through your nose as the water hits the face and nostrils. Breach your mask’s seal from the top. Either slowly pull the frame away very slightly and use a fingertip to break the seal, or gently pinch the top of the silicone skirt together to cause a fold. Maintain the natural breathing pattern you learned in step one, only holding your nostrils if you feel the urge to inhale through your nose.

Step 3: Press the frame of your mask

Begin with a comfortable breathing pattern. Inhale through the mouth, not the nose, as outlined in step one. Firmly press the frame at the top edge of your mask — not the skirt — using your fingertips or the heel of your palm to create a ‘hinge.’ This allows the air pressure you’re about to add to blast water out of the bottom of the mask. Don’t lift the bottom edge of the mask – it’s unnecessary and you’ll simply allow water to flood back in.

Step 4: Breathe out

Take a slow, deep inhalation through your mouth. Then, begin to firmly exhale through your nose while maintaining the pressure on the very top of the mask’s frame. The exhalation shouldn’t be a burst or a gentle blow, but rather forceful blow a lasting one or two seconds. If one breath is not sufficient, repeat the process until there is just a small amount of water at the bottom of your mask. With practice, you’ll likely learn to clear your mask in one breath.

Step 5: Look up

To get the last of the water out, look up at a 45-degree angle as you finish your exhale. This assists the hinge effect of pressing on your mask and drives what’s left of the water from the mask. Don’t begin this stage until the final stages of the process or you’ll simply tip water up your nose.

Step 6: Remove rogue water

If wearing a twin-lens mask, you may find one lens fully cleared and the other lens still has a bit of water inside. In this case, simply put pressure on the frame above the cleared lens and repeat steps four and five. When done, resume your normal diving breathing pattern.

The rest is practice. And, with practice, you’ll find that clearing your mask needn’t be stressful and doing so confidently will help you become a competent diver.