What to Do If… Mask Fogs, You Run Low on Air, Lose Your Buddy or Hit a Current

The universal response: Stop – Breathe – Think – Act

1. Stop: stop swimming and hold your position; hold on to your buddy or a rock (not coral) if needed.
2. Breathe: take several slow, deep breaths, focusing on long exhales.
3. Think: what exactly is the problem? What are my options?
4. Act: deal with it calmly, and signal your buddy.

Almost every serious diving incident begins with a small problem that turned into panic. These steps break that chain.

Your mask fogs up

• Let a little water into the mask by lifting the top edge slightly.
• Swirl the water around the lens by tilting your head.
• Clear the mask: press the top of the frame against your forehead, look slightly up, and exhale steadily through your nose.

Prevent it next time with proper anti-fog and cleaning. See dive masks.

Your mask floods or gets knocked off

• Keep breathing from your regulator through your mouth. Your air supply is unaffected.
• If knocked off: find it (it's usually hanging around your neck, or check behind you), put it on, and clear it.
• Keep your eyes closed or squinting if the salt stings; exhale gently through your nose to stop water entering it.
• Signal your buddy if you need help.

You're running low on air

• Signal your buddy (fist to chest) and your guide.
• Begin a normal, slow ascent together, with a shorter safety stop if necessary.
• Stay close to your buddy in case you need to share air.

Prevention: check your gauge every few minutes, agree a turn pressure and an ascent pressure (for example, start ascending at 50–70 bar), and signal your air when asked.

You're out of air

Options, in order of preference:

1. Get your buddy's alternate air source: signal "out of air" and "share air", take their octopus, hold on to each other (right arm to right arm or BCD straps), and ascend slowly together.
2. Controlled Emergency Swimming Ascent (CESA): if your buddy is too far away and you're shallow enough (within roughly 9 m), swim up at a normal ascent rate while exhaling continuously, for example making an "ahhh" sound.
3. Buoyant emergency ascent: a last resort if you're too deep or can't swim up. Drop your weights and exhale continuously.

At the surface, inflate your BCD orally or drop your weights to stay afloat.

You lose your buddy

1. Stop and look around for up to one minute: turn slowly, look up and down, look for bubbles and torch light.
2. Ascend slowly (with a safety stop, if air allows).
3. Reunite at the surface.
4. If your buddy doesn't appear within a few minutes, alert the boat or shore.

See the buddy system.

You're caught in a strong current

• Don't fight it head-on. You'll exhaust yourself and burn air.
• Get close to the reef or bottom, where current is weaker, and use the terrain for shelter.
• If you must move against it, swim across the current rather than directly into it.
• If the current is carrying you away and you can't return, ascend with your buddy, deploy your SMB, and wait at the surface for the boat. That's what drift diving plans for anyway.
• At the surface: inflate your BCD, stay together, use your whistle and SMB, and don't try to swim against a strong current to the boat.

Leg cramp

Stop kicking, grab the tip of your fin and pull it towards you to stretch the calf. Massage it gently. Signal your buddy, who can tow you if needed. See fitness for prevention.

Your regulator free-flows

Don't seal your lips on it. Hold the mouthpiece in your mouth loosely, let excess air escape out the sides, and sip what you need. Signal your buddy, switch to your octopus or theirs if necessary, and end the dive with a controlled ascent.

You're entangled in line or net

Stop moving (spinning makes it worse). Signal your buddy. Work out where you're caught, and have your buddy free you or cut it with a line cutter. Always carry a cutting tool on open-water dives.

Vertigo or disorientation

Hold on to something solid or your buddy, focus on a fixed object and your bubbles (they go up), and ascend slowly if it doesn't pass. Vertigo after a dive with ear pain needs medical assessment. See ears.

You feel anxious or panicky

Stop, hold on to your buddy, breathe out slowly, and focus on something close. If it doesn't pass, signal and ascend slowly together. Ending a dive early is always OK. More in overcoming fears.

Frequently asked questions

What should I do if I run out of air underwater?

Signal your buddy and breathe from their alternate air source, then ascend slowly together. If no buddy is nearby and you're shallow, make a controlled emergency swimming ascent while exhaling continuously.

How do I stop my mask from fogging underwater?

Let a little water in, swirl it around, and clear it by exhaling through your nose. Before the next dive, clean the lens properly and use anti-fog.

What if I get swept away by a current?

Don't fight it. Stay with your buddy, ascend safely, deploy your surface marker buoy and wait for the boat.