Freediving Safety Rules - The Buddy System Explained

Freediving has a reputation as an extreme sport, but most of the risk comes down to a handful of rules being skipped. Follow these freediving safety rules on every dive and the sport becomes remarkably safe. Ignore them, especially the buddy system, and even shallow dives can turn fatal.

This guide explains the rules most training agencies teach, why each one exists, and how to apply them in the pool, on a line and in open water. It is not a substitute for a course; it is a reference to help you remember what you learned.

Rule 1 - Never freedive alone

This is the rule that saves the most lives. The main danger in freediving is hypoxic blackout, which can happen without warning even to experienced divers on dives that felt easy. A blackout is usually harmless if someone is there to keep your airway out of the water. Alone, it is frequently fatal.

Never dive alone means:

• No solo breath-hold training in water, whether in a pool or a bathtub.
• No solo spearfishing or snorkeling breath-hold dives.
• No diving with a buddy who is not trained or is not actually watching.

A friend on the boat is not a buddy. A buddy is someone in the water who is trained, knows your plan and can reach you. If you are looking for someone to train with, see our guide on how to find a freediving buddy.

Rule 2 - One up, one down

One up, one down means only one diver in the pair is underwater at a time. The other stays at the surface, rested, breathing normally and fully focused on the diver.

What the surface buddy does

1. Before the dive - confirms the plan, target depth or time and expected duration.
2. During the descent - watches the diver, tracks time and looks for signs of trouble.
3. On the ascent - for depth dives, descends to meet the diver, often at about a third of the dive depth, timed to arrive as the diver comes up. They stay face to face and ascend together.
4. At the surface - stays within arm's reach and watches the recovery for at least 30 seconds.
5. Only then - takes their own turn once both are fully recovered.

Groups and line sessions

In groups, the principle still applies. Each diver needs a dedicated buddy who is not diving at the same time. Never share one safety diver between two people diving simultaneously.

Rule 3 - Watch the last 30 seconds

The most dangerous moments in a freedive are the last few meters of the ascent and the first 30 seconds or so at the surface. As you rise, the water pressure drops, and so does the partial pressure of oxygen in your lungs. At the same time, your body is still using oxygen. The result is that oxygen delivery to the brain can drop sharply right when you think the dive is over. Our freediving blackout and samba guide explains the physiology in detail.

For the buddy, this means:

• Do not look away the moment the diver surfaces.
• Stay close enough to grab them if they lose control.
• Watch their face, eyes and breathing, not just whether their head is out of the water.
• Do not start your own breathe-up until they have completed the surface protocol and look fully normal.

Rule 4 - Follow the surface protocol

The surface protocol is a short routine every diver does immediately after surfacing. It helps the body recover and shows the buddy the diver is conscious and in control. Exact wording varies by agency and competition rules, but it usually looks like this:

1. Grab the buoy or line for support.
2. Remove the mask or nose clip so your face is clear.
3. Perform recovery breaths, sometimes called hook breathing - a quick passive exhale, then a full inhale held briefly against slight pressure before exhaling, repeated several times.
4. Give a clear OK hand sign.
5. Say "I am OK" so your buddy can hear you are fully conscious.

Recovery breaths help keep pressure in the lungs and support oxygen delivery during those critical first seconds. Practice them on every dive, even easy ones, so they become automatic when you need them most.

Rule 5 - Set up your line properly

For any depth training in open water, dive on a buoy and line rather than free in the blue.

A safe basic setup

• Buoy with a dive flag - large enough for both divers to rest on, clearly visible to boat traffic.
• Weighted line - running straight down, with a bottom weight or plate at your planned maximum depth.
• Depth set below your target - so the line ends just beyond the deepest dive of the session, not miles beyond it.
• Lanyard - a short leash clipped from your wrist or ankle to the line, with a quick-release, so you cannot drift away.
• Bottom stop or marker - a tag, plate or ring so you know you have reached your target.

Many groups also use a counterweight system that lets a buddy at the surface pull a diver up quickly in an emergency. That is excellent practice for deeper training and should be set up by someone trained to do so.

Make sure your weighting keeps you positively buoyant near the surface, so that a diver who loses consciousness in the shallow zone tends to float.

Rule 6 - Never hyperventilate

Hyperventilating, or breathing fast and deep before a dive, lowers the carbon dioxide in your blood. Because carbon dioxide drives the urge to breathe, you lose your early warning system and can run out of oxygen before you feel the need to surface. It does not meaningfully increase the oxygen you carry.

Instead, use a calm, slow breathe-up with relaxed exhalations. Our freediving breathe-up technique guide covers how to prepare properly.

Rule 7 - Respect surface intervals and progression

• Rest properly. A common guideline is a surface interval of at least two to three times the length of your dive, and longer for deep dives.
• Warm up first. Start every session with easy, shallow dives.
• Progress slowly. Add a few meters or a few seconds at a time, only after a dive feels completely relaxed.
• Stop while it is still fun. Fatigue, cold and dehydration all raise risk. End the session before you are exhausted.
• Never push through pain. Ear, sinus or chest pain is a signal to turn the dive.

Avoid freediving after scuba diving on the same day unless you have clear guidance from your training agency, and seek advice on how long to wait between the two.

Rule 8 - Read the conditions

Before getting in, the buddy pair should agree that conditions are suitable. Call it off if any of these look wrong:

Many incidents start with a diver who was tired, cold or stressed before the first dive. The decision not to dive is always a valid one.

Rule 9 - Get trained and keep practicing

Reading rules is not the same as being able to perform a rescue. Take a recognized beginner course, which teaches the buddy system, surface protocol and basic rescue under the supervision of a qualified instructor. Our certification levels guide compares the main pathways.

After the course, keep the skills fresh. Practice a rescue drill with your buddy at the start of a session from time to time, and take a refresher if you have been out of the water for a while. Planning sessions with the same trusted partner makes this much easier, and it is one of the reasons BuoyBuddy, the freediving buddy-finder app coming soon to iOS and Android, lets you plan dives and sessions together.

To recap, here are the freediving safety rules in short:

• Never freedive alone.
• One up, one down, every dive.
• Watch the diver for at least 30 seconds after surfacing.
• Use the surface protocol on every dive.
• Dive on a buoy, flag and line, with a lanyard for depth.
• Never hyperventilate.
• Rest at least two to three times your dive time, and progress slowly.
• Check conditions and your own body before getting in.
• Get trained and practice rescues regularly.

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