The Complete Guide to Swimming Breathing Technique: From Underwater Exhalation to Bilateral Breathing

If you had to pick the single most critical skill in swimming, the answer is unquestionably breathing. You can have a perfect stroke and powerful kicks, but if your breathing rhythm is off, all that effort falls apart.

Many swimmers assume that running out of breath while swimming is a fitness problem, but in reality 90% of breathing difficulties come from incorrect breathing technique. This article starts with the most basic underwater exhalation and progresses step by step to bilateral breathing and pace-based breathing.

The Basic Principles of Swimming Breathing

The biggest difference between swimming breathing and breathing during land-based sports is:

	Land Sports	Swimming
Inhale	Anytime	Only when the mouth is above water
Exhale	Passive, natural	Must be actively completed underwater
Rhythm	Freely controlled	Limited by stroke rhythm
Resistance	None	Water pressure increases exhalation resistance

Core principle: use the time underwater to exhale, and only inhale when your mouth breaks the surface.

The most common mistake beginners make is holding their breath underwater, then trying to exhale and inhale both in the brief moment their mouth is above water. The problem is that there simply isn’t enough time to complete both actions in that short window, resulting in insufficient inhalation, a buildup of carbon dioxide, and increasing breathlessness the longer you swim.

Step One: Learn to Exhale Underwater

This is the foundation of everything. If you take away only one technique from this article, make it this one.

Standing Practice

1. Stand in shallow water, with the water at chest height
2. Take a deep breath and submerge your face in the water
3. Exhale slowly and continuously through your nose and mouth
4. Once you’ve finished exhaling, lift your head and inhale
5. Repeat 10-15 times

Key Points

• Exhale continuously without interruption: don’t blow it all out at once — exhale slowly, like a sigh
• Exhale through both the nose and mouth simultaneously: exhaling through the nose prevents water from entering the nasal passage
• Exhalation intensity: think of blowing bubbles — a steady stream of air, not an explosive burst
• Finish exhaling before lifting your head: this ensures your lungs are mostly empty, so when you lift your head you naturally draw in fresh air

Common mistake: many people believe they’re exhaling underwater, but in reality their mouth is only slightly open and most of the air stays trapped in their lungs. You should be able to see clear bubbles rising from the water.

Step Two: Freestyle Unilateral Breathing

Once you’ve mastered underwater exhalation, integrate it into your freestyle stroke.

Breathing Timing

In freestyle, the breath should happen at the moment the pulling arm finishes its push and begins the recovery:

1. As the arm completes its push phase and is about to leave the water
2. The body naturally rotates to the side
3. The head follows the body’s rotation, bringing the mouth above the surface
4. Inhale quickly
5. The head returns to a neutral position (face down)
6. Continue exhaling underwater

Head Turning Technique

Correct Movement	Common Mistake
The head follows the body’s rotation	Turning the head alone (without body rotation)
One eye stays underwater, one eye above	Lifting the entire face out of the water
Inhaling from the “bow wave trough”	Excessively lifting the head to find air
Gaze directed sideways and slightly backward	Gaze directed forward or up at the ceiling

The “Bow Wave”: as your head moves forward through the water, the water in front gets pushed aside, creating a trough below the surface along the side of your head. By using this trough, you can inhale without needing to lift your head very high.

Breathing Rhythm (Unilateral)

Breathing Pattern	Description	Suitable For
Breathe every 2 strokes	Breathe once per stroke on the same side	Long distance, aerobic training
Breathe every 4 strokes	Breathe once every two stroke cycles	Middle-distance pacing

Step Three: Bilateral Breathing

Bilateral breathing means alternating between breathing on the left and right sides. The most common pattern is breathing every 3 strokes, which naturally alternates the breathing side left and right.

Benefits of Bilateral Breathing

1. Balanced stroke mechanics: avoids the body asymmetry caused by breathing on only one side
2. Better water feel and balance: more even body rotation on both sides
3. Racing advantage: allows you to see competitors and buoys on both sides
4. Reduces the risk of swimmer’s shoulder: lowers the excessive strain on a single shoulder
5. Open water adaptability: lets you breathe on whichever side has calmer waves

Progressive Learning Method

Stage One: Wall Practice

• Hold onto the pool wall with both hands, submerge your face, and exhale
• Turn to the right first to inhale, then return to the water and exhale
• Then turn to the left to inhale
• Repeat until both sides feel comfortable

Stage Two: Kicking + Breathing

• Extend both arms forward and kick to move forward
• Every 6-8 kicks, turn to one side and inhale
• Practice the weaker side first
• Gradually alternate between both sides

Stage Three: Single-Arm Swimming + Breathing

• One arm extended forward, the other arm pulling
• Breathe on the same side as the pulling arm
• Practice separately: left arm pulling with right-side breathing, and right arm pulling with left-side breathing

Stage Four: Full Stroke, Breathing Every 3 Strokes

• Normal freestyle, breathing once every 3 strokes
• It’s normal for one side to feel awkward at first
• Consistent practice for 2-3 weeks will bring noticeable improvement

Advanced Breathing Patterns

Hypoxic Training

Challenge your breath control by reducing breathing frequency:

Drill	Breathing Pattern	Difficulty
Breathe every 3 strokes	Standard bilateral	Moderate
Breathe every 5 strokes	5-stroke breathing	Fairly high
Breathe every 7 strokes	7-stroke breathing	High
Progressive	3-5-7-9-7-5-3	Gradually escalating

Note: the purpose of hypoxic training is to improve breath control and mental tolerance, not to induce oxygen deprivation. If you feel dizzy or uncomfortable, resume normal breathing immediately.

Pace-Based Breath Control

Use different breathing strategies at different paces:

• Easy aerobic: breathe every 3 strokes (bilateral)
• Lactate threshold: breathe every 2-3 strokes
• High-intensity intervals: breathe every 2 strokes
• All-out sprint: breathe every 2 strokes, and in the final 15 meters you may need to breathe every stroke

Breathing Technique Training Menu

Breathing-Focused Training Session (60 minutes):

Warm-up: 200m freestyle (focus on underwater exhalation, no rush)

Underwater Exhalation Drills:
  Standing exhalation × 10 reps
  Floating exhalation (front float) × 5 reps, stand up after fully exhaling each time

Unilateral Breathing Reinforcement:
  4×50m breathing only on the weak side
  4×50m breathing only on the strong side

Bilateral Breathing Drills:
  4×75m breathing every 3 strokes
  4×50m breathing every 5 strokes

Hypoxic Challenge:
  4×25m progressive breathing (3-5-7-5 strokes)

Integrated Swimming:
  4×100m freestyle
    First 50m: breathe every 3 strokes
    Last 50m: breathe every 2 strokes

Cool-down: 200m backstroke

Total distance: 1,700m

Frequently Asked Questions

Q: What should I do if I swallow water when turning to breathe?

The most common causes are lifting the head too high or exhaling too late. Solutions:

• Make sure you’ve finished exhaling underwater before you turn your head
• Don’t lift your head — turn it to the side so your mouth is just at the water surface
• The instant your mouth clears the surface, blow out a small forceful puff of air first (a quick “puh”) to clear any water near your mouth

Q: I can only breathe on my right side — my left side doesn’t work at all?

This is completely normal. Breathing on the non-dominant side feels like “writing with your non-dominant hand.” The only solution is plenty of practice. It’s recommended to breathe on your weaker side during the warm-up and cool-down portions of every training session; noticeable improvement typically comes after 2-3 weeks.

Q: What’s the best breathing strategy for long-distance swimming?

For long distances (1,500m and beyond), it’s recommended to breathe every 2 strokes to ensure adequate oxygen supply. If your bilateral breathing technique is well developed, you can switch breathing sides every few minutes to reduce fatigue on one side.

Summary

The core of swimming breathing technique is simple: fully exhale underwater, and only inhale quickly when you surface. But such a simple principle takes a great deal of practice to become second nature. Starting today, do 10 reps of underwater exhalation practice at the pool wall before every swim, reminding yourself that “exhaling” is the true key to swimming breathing. Once breathing is no longer a problem, you’ll find you have far more attention to devote to technique and pacing — and swimming will shift from a struggle into something you truly enjoy.

Related Reading

• How Swimming Trains the Respiratory System: Improving Lung Capacity and Asthma
• Swimming Breathing Technique: Pros and Cons of Side Breathing vs. Bilateral Breathing
• Lung Capacity Training in Swimming: The Physiology of Breath-Holding Drills and Breathing Rhythm
• Open Water Breathing Rhythm: Maintaining Technique Over Long Distances