Freediving Safety: Essential Rules Every Diver Must Know

Freediving has an excellent safety record — but only among people who follow the rules. Every freediving accident on record violated at least one of the principles covered here.

People are sometimes surprised to learn that freediving is considered one of the safest water sports when practiced correctly. The surprise makes sense — holding your breath underwater sounds inherently risky. But the risk is almost entirely controllable. The accidents that do occur are almost always traceable to a specific moment where a known rule was broken, usually the most fundamental one: diving alone.

This is not a list of suggestions. These are the non-negotiable rules of the sport.

Rule 1: Never Dive Alone

This is the only absolute in freediving — the one rule with no exceptions and no negotiable circumstances.

Why it exists: Shallow water blackout (SWB) is a loss of consciousness caused by hypoxia (low oxygen). It occurs silently, without warning, and often within 5 meters of the surface just as a diver is finishing an ascent. A blackout in the water, unattended, results in drowning within 60–90 seconds.

What a trained buddy does: A freediving buddy is not a spectator. They are an active safety diver who watches every ascent, enters the water to meet their partner at 5 meters on deeper dives, and knows exactly how to respond to LMC (loss of motor control) or full blackout at the surface.

The rule in practice:

• One person dives at a time (One-Up, One-Down)
• The buddy watches from the surface during the entire dive
• The buddy meets the diver at 5 meters on any dive deeper than 15 meters
• If the diver doesn't surface in the expected time or shows abnormal behavior on ascent, the buddy enters the water immediately

What counts as "alone": Any situation where no one would notice if you blacked out and respond within 10–15 seconds. This includes: diving in the ocean while your friend snorkels 30 meters away, pool breath-hold training while someone else swims laps, or "I'm just doing a quick breath-hold in the bathtub."

Rule 2: Surface Intervals — The 1:2 Minimum Ratio

After every dive, you must rest on the surface for at least twice the duration of your dive before your next dive.

Why it exists: After a breath-hold, your blood oxygen has been depleted and CO2 has accumulated. It takes time for your respiratory system to fully clear CO2 and re-saturate your blood with oxygen. If you dive again before this process completes, each successive dive starts from a progressively worse physiological baseline. The risk of blackout accumulates faster than most divers realize.

The rule in practice:

• 1-minute dive → 2-minute rest minimum
• 2-minute dive → 4-minute rest minimum
• 3-minute static → 6-minute rest before the next static

Common mistake: Taking "enough breaths" instead of waiting for the full time. Recovery breathing brings CO2 down quickly and makes you feel ready. But oxygen saturation and neurological recovery take longer than the absence of discomfort suggests.

Rule 3: Recovery Breathing Every Time

Every surfacing from a breath-hold — no exceptions — must be followed by three to four full diaphragmatic recovery breaths before you do anything else.

Why it exists: The last phase of ascent, from 5 meters to the surface, is the highest-risk moment of any dive. Your lungs are expanding, partially reducing the partial pressure of remaining oxygen in your bloodstream. If you surface and immediately try to speak, remove your snorkel, or signal before breathing, you may black out in those few seconds.

The protocol:

1. Surface → immediate recovery breath 1 (quick, medium inhale, passive exhale)
2. Recovery breath 2 (full, slow diaphragmatic breath)
3. Recovery breath 3 (full, slow)
4. Give the OK signal to your buddy
5. Your buddy mirrors the OK signal back
6. Now you may remove your snorkel and speak

Important: Your buddy should respond to your OK signal. If they don't within 2–3 seconds, something may be wrong with their awareness. Both sides of the buddy system must be active.

Rule 4: Know the Difference Between LMC and Blackout

Loss of Motor Control (LMC)

LMC is the precursor to blackout. The diver is still conscious but loses voluntary motor control — they may twitch, convulse, go limp, or behave irrationally. Eyes remain open. The diver may respond to voice but cannot respond reliably.

LMC response: Hold the diver's head above water. Do not enter the water unless necessary — LMC typically resolves in 10–20 seconds at the surface with fresh air. Speak calmly: "Breathe, you're okay." Do NOT leave the diver alone. If LMC does not resolve within 30 seconds, treat as blackout.

Blackout (Shallow Water Blackout)

Full loss of consciousness. The diver's eyes may close or roll back. They may inhale water if the airway is not protected. This is a medical emergency.

Blackout response (at the surface):

1. Lift the diver's face out of the water, supporting the neck and head
2. Remove the snorkel and mask immediately to clear the airway
3. Call for help loudly
4. Tap the cheek and call the diver's name firmly
5. Most blackouts resolve spontaneously within 15–30 seconds of oxygen reaching the brain
6. If the diver does not regain consciousness, begin rescue breathing and call for emergency services

Critical: Do not tilt the head back. This can allow water in the mouth to enter the airway. Hold the head level and face up.

Blackout response (underwater): A buddy who sees their partner limp and unresponsive at depth must immediately perform an emergency ascent:

• Get behind the diver, hold their chin with both hands, push off the bottom or line and kick to the surface
• Maintain the diver's head level and back throughout ascent
• Get the face out of the water, remove snorkel/mask, begin surface protocol

Rule 5: Recognize When Not to Dive

Never dive when:

• You have a cold, sinus congestion, or blocked ears — equalization will be impossible or dangerous
• You have consumed alcohol in the last 12 hours — alcohol impairs judgment and increases hypoxia risk
• You are fatigued — tiredness dramatically increases blackout risk at shallower depths
• You have any cardiac symptoms (palpitations, chest tightness, shortness of breath)
• You are on medications that affect cardiovascular response or consciousness
• You feel "off" without a clear reason — trust your body

Regarding hyperventilation: Never deliberately hyperventilate before a dive. Breathing rapidly to "top up oxygen" actually suppresses CO2 — the signal that tells you to breathe — and is the direct cause of most modern freediving fatalities.

Rule 6: Equalize Early and Often

Ear barotrauma (middle ear squeeze) is the most common injury in freediving. It's entirely preventable.

• Begin equalizing before you submerge
• Equalize every 1–2 meters on descent
• If you feel pressure, ascend slightly and try again — never force an equalization
• Never dive with a blocked nose or sinus congestion

For detailed technique guidance, see our post on Frenzel Equalization.

Rule 7: Ascend Slowly and Look Up

Ascent speed: 1 meter per second maximum. Faster ascents reduce the partial pressure of oxygen in your blood more quickly, increasing blackout risk.

Look up on ascent: This creates a hydrodynamic position for ascent and keeps your airway in a good position. It also means you can see your buddy coming to meet you.

Hands up: In the final 5 meters of ascent, raise one arm above your head. This protects your head in case your buddy is directly above you, and signals to your buddy that you're about to surface.

Rule 8: The Buddy Check

Before every dive session, both partners confirm:

• Both agree on the dive plan (max depth, max time, bail-out signals)
• Both understand the surface signal protocol
• Both know the emergency procedure
• Both are physically and mentally ready to dive

The buddy check takes 60 seconds. It ensures that if something goes wrong, both people know what to do without confusion or hesitation.

Formal Safety Training

The rules above are introduced in our Wave 1 course, but safety proficiency grows with experience and dedicated training. Our Rescue and Safety Workshop covers:

• In-water blackout response scenarios
• Emergency ascent technique
• LMC and blackout recognition drills
• Simulated rescue in controlled pool conditions

The workshop is open to Wave 1 certified divers and above. Many students take it before their first trip to open water — knowing exactly what to do in an emergency changes how relaxed you are in the water.

See our full Safety page for an overview of how we structure safety into every session at ORO.

Freediving is safer than most people imagine — and less safe than it looks when someone dives alone. The rules exist because people have been hurt when they were ignored. Following them consistently makes the sport profoundly enjoyable because you're free to focus on the experience rather than manage the risk.

Learn it right from the start. Our Wave 1 Course covers all safety protocols with in-water practice, not just theory.

Book a Course | Learn About Safety at ORO