How to Equalize When Freediving

Equalization is the single skill that determines how deep you can freedive. Your breath hold might be 3 minutes. Your technique might be flawless. But if you cannot equalize your ears, you stop at 5 meters.

This guide covers what equalization is, why it matters, the techniques that work for freediving, how to practice before your course, and what to do when it stops working at depth.

What Is Equalization

When you descend in water, pressure increases. At 10 meters depth, the pressure on your body is double what it is at the surface. At 20 meters, it is triple.

Your lungs handle this compression naturally. They shrink as pressure increases and expand as you ascend. But your ears and sinuses contain air spaces that do not compress on their own. As you descend, the water pressure pushes inward on your eardrums. If you do not actively push air back into those spaces to balance the pressure, the increasing force on your eardrums causes pain and eventually injury.

Equalization is the act of sending air from your throat into your middle ear and sinuses to match the surrounding water pressure. You do this every 1 to 2 meters during descent. When done correctly, it feels like a gentle click or pop in your ears. When done incorrectly, or not at all, it feels like someone pressing their thumbs into your eardrums.

Why Scuba Equalization Does Not Work for Freediving

If you have scuba dived, you probably learned the Valsalva maneuver: pinch your nose, close your mouth, and blow. Air pressure from your lungs forces open the Eustachian tubes and equalizes your ears.

Valsalva works fine in scuba because you have an unlimited air supply and you descend slowly. In freediving, it has two serious problems.

First, Valsalva uses air from your lungs. As you descend, your lungs compress and the volume of available air decreases. Below about 20 to 25 meters, there is not enough lung volume left to generate the pressure needed for a Valsalva. You hit a wall.

Second, Valsalva is forceful. It uses the chest and abdominal muscles to push air upward. This increased effort raises heart rate, consumes oxygen faster, and creates tension in the body. In freediving, tension is the enemy. Every part of a freedive should be as relaxed as possible.

This is why every serious freediving course teaches you Frenzel instead.

The Frenzel Technique

Frenzel equalization uses the tongue as a piston to push air into the ears. Instead of blowing from the lungs, you trap air in your mouth and throat, close the back of your throat (the glottis), and use the back of your tongue to compress that trapped air upward through your Eustachian tubes.

Think of it this way: Valsalva is like inflating a balloon by blowing from your chest. Frenzel is like inflating a balloon by pushing with your tongue while the rest of your body stays relaxed.

How Frenzel Works Step by Step

Step 1: Fill your mouth with air. Take a normal breath, then trap a small amount of air in your mouth and cheeks. Your cheeks should puff out slightly, like you are about to gargle.

Step 2: Close your glottis. The glottis is the valve at the back of your throat that closes when you hold your breath. You use it every time you grunt, cough, or lift something heavy. Close it now. You should feel a seal at the base of your throat that separates the air in your mouth from the air in your lungs.

Step 3: Pinch your nose. Using your mask or nose clip, seal your nostrils so air cannot escape.

Step 4: Push with your tongue. With your glottis closed and nose pinched, push the back of your tongue upward and backward against the roof of your mouth. This compresses the air trapped in your oral cavity and forces it into your Eustachian tubes. You should feel a click or pop in both ears as the air enters your middle ear space.

The entire motion takes less than a second. With practice, it becomes as automatic as swallowing.

The Key Difference

Notice what does not move during Frenzel: your chest, your diaphragm, your abdominal muscles. All the work happens in your mouth and throat. This is why Frenzel works at depths where Valsalva fails. You are not relying on lung volume. You are using a small pocket of air in your mouth, compressed by your tongue.

How to Practice Frenzel on Land

You do not need water to learn Frenzel. In fact, you should practice on land first until the technique is comfortable before attempting it during a dive.

Exercise 1: Find Your Glottis

Say the letter "K" out loud. Feel where your tongue touches the roof of your mouth at the back? That is near your glottis. Now say "K" but stop just as your tongue makes contact, before releasing the sound. Hold that position. You have just closed your glottis.

Another way: try to exhale with your mouth and nose closed. Feel the pressure build in your throat? That seal is your glottis.

Exercise 2: Tongue Piston

Puff your cheeks with air. Close your glottis (like in Exercise 1). Now, keeping your mouth closed and glottis locked, push the back of your tongue upward. Your cheeks should deflate slightly as the air compresses. Release and repeat. Do 10 repetitions.

This is the core Frenzel motion. You are learning to use your tongue as a piston to move air independently of your lungs.

Exercise 3: Equalize Without Water

Pinch your nose with your fingers. Puff your cheeks with air. Close your glottis. Push with your tongue. You should hear or feel a pop in one or both ears. That is equalization.

If only one ear pops, try tilting your head slightly to the opposite side and repeating. Asymmetric equalization is common and usually resolves with practice.

Exercise 4: Continuous Equalization

Pinch your nose and equalize 5 times in a row without taking a new breath. Each time, use only the tongue piston motion. This simulates what you will do during a descent, where you equalize every 1 to 2 meters without stopping to think about it.

Practice these exercises for 5 to 10 minutes a day in the week before your freediving course. By the time you arrive, the motion will feel natural.

When to Equalize During a Dive

The most important equalization happens at the surface. Before you duck dive, take your final breath and perform one equalization while your head is still above water. This pre loads your middle ear with air and gives you a head start.

As you begin your descent, equalize every meter for the first 10 meters. The pressure change is greatest near the surface (Boyle's law: pressure doubles in the first 10 meters, but only increases by 50% between 10 and 20 meters). This means the first 10 meters demand more frequent equalization than the deeper sections.

Below 10 meters, you can often equalize every 2 to 3 meters as the rate of pressure change slows. But if you feel any tightness or pressure in your ears, equalize immediately. Do not wait.

Common Equalization Problems

One Ear Will Not Equalize

This is the most common issue. One Eustachian tube is slightly narrower or more congested than the other. Try tilting your head so the stubborn ear faces the surface, then equalize. Gravity helps the air find its way into the tube. If it still will not equalize, do not force it. Ascend 1 to 2 meters and try again.

Equalization Works on Land but Not in Water

Water pressure, body position, and anxiety all affect equalization. Head down position (which is your orientation during a freedive) changes the dynamics compared to sitting upright on land. This is why practicing the exercises is important, but nothing replaces actual water training with an instructor watching your technique.

Equalization Stops Working at a Certain Depth

If you are using Valsalva, you will hit a wall around 20 to 25 meters as your lungs compress and cannot generate enough pressure. Switch to Frenzel to go deeper.

If you are using Frenzel and it stops working, you may have run out of air in your mouth cavity. The solution is a technique called the mouthfill, taught in advanced courses: you fill your mouth completely with air at around 15 to 20 meters and use that stored air for all equalization below that point.

Congestion Makes Equalization Impossible

A cold, allergies, or sinus congestion can make equalization difficult or impossible. Swollen Eustachian tubes do not open easily regardless of technique. Do not dive when congested. The risk of barotrauma (ear or sinus injury from pressure) is real. Wait until you are clear.

Some divers use nasal decongestant sprays before diving. This can work short term, but if the decongestant wears off at depth, your Eustachian tubes swell shut and you cannot equalize on ascent (a reverse block). This is painful and potentially dangerous. Do not use decongestants unless your instructor specifically advises it.

What Happens If You Force It

If you push through equalization pain and keep descending, you risk a middle ear barotrauma. This ranges from mild (temporary hearing muffling, slight pain for a day or two) to serious (eardrum perforation, blood in the ear canal, vertigo, weeks of recovery). In rare cases, it can damage the inner ear and affect hearing permanently.

The rule is absolute: if you cannot equalize, you stop descending. (For more on freediving safety, read Is Freediving Safe?) Turn around. Ascend a meter or two and try again. If it still does not work, end the dive. No depth target is worth an ear injury. Your ears will heal from a skipped dive. They may not heal from a forced one.

Equalization Tips for Your First Course

• Start early. Equalize at the surface before you duck dive, then equalize again immediately as you begin descending. Getting ahead of the pressure is easier than catching up.
• Equalize often. Every meter for the first 10 meters. It is better to equalize 10 times more than necessary than to be one equalization too late.
• Stay hydrated. Dehydration thickens the mucus in your Eustachian tubes and makes equalization harder. Drink plenty of water the day before and the morning of your dive.
• Avoid dairy before diving. Milk, cheese, and yogurt can increase mucus production in some people. Eat a light breakfast without dairy on dive days.
• Do not dive with a cold. Wait until your sinuses are completely clear. Pushing through congestion causes injuries.
• Relax your jaw. Tension in your jaw tightens the muscles around your Eustachian tubes. Before each dive, wiggle your jaw, open your mouth wide, and consciously relax the muscles in your face and neck.
• Tell your instructor. If equalization is not working, say so. Your instructor can adjust your descent speed, suggest technique modifications, or change your body position to help. Staying quiet about equalization problems leads to injuries.

Beyond Frenzel: The Mouthfill

Frenzel equalization works reliably to about 25 to 30 meters for most divers. Beyond that, the air in your mouth and throat compresses to a volume too small for the tongue piston to work effectively.

The mouthfill technique solves this. At around 15 to 20 meters (while you still have enough air), you fill your entire mouth and cheeks with as much air as possible in a single movement. You then use that stored air for all remaining equalization during the dive, pushing tiny amounts into your ears with micro movements of the tongue.

Mouthfill is taught in the Advanced Freediving Course (Level 2). It requires solid Frenzel technique as a foundation. If you are taking a beginner course, focus entirely on Frenzel. Mouthfill comes later.

Learn Equalization Properly

Reading about equalization is a starting point. Practicing the land exercises will prepare you. But the technique clicks when an instructor watches you do it in the water and gives you real time feedback on what you are doing right and what needs adjustment.

In a freediving course on Koh Samui, equalization training starts on Day 1 in shallow water before you attempt any depth. Your instructor checks your technique at every stage. With a maximum of 3 students, there is time to troubleshoot your specific equalization challenges rather than rushing through a checklist.

If equalization is the skill you are most nervous about, you are not alone. It is the number one concern for beginner freedivers. It is also the skill that improves the fastest with proper instruction.

Send a WhatsApp message if you have questions about equalization or want to check availability for a course. Many students message with technique questions before they arrive, and that conversation helps your instructor prepare for your specific needs.