6 Reasons Swimming Builds the Ultimate Foundation for Freediving

It took me some time to truly accept it myself—but swimming is one of the most powerful foundations for freediving performance.

In my first two years of freediving, I believed the only way to improve was simple: dive more. But over time, that perspective shifted completely. Structured swimming training transformed the way I prepare—not only for depth, but also for pool disciplines.

Swimming provides an incredibly efficient environment to develop the exact systems freedivers rely on: movement efficiency, endurance, CO₂ tolerance, and a strong mind–body connection. And when I say swimming, I don’t mean just going back and forth for an hour. I’m talking about intentional, structured training—technical drills, sprint work, intervals, 25-meter FRC dives combined with surface swimming, and transitions between strokes like butterfly, freestyle, and breaststroke. It’s about building strength in the water, refining technique, and creating a solid physiological foundation.

I was first introduced to this approach through my former pool trainer, Goran Čolak. When I started working with him, I realized how little I actually knew. I still remember receiving my first weekly plan—“easy crawl, then faster, then sprint”—and not even knowing how to properly swim freestyle.

In my first pool training sessions in Zurich, I would skip the 200-meter warm-up crawl altogether. Partly out of embarrassment because I could not crawl much further than one full lane, partly out of ignorance. I told myself: I’m here to freedive, not to swim. Even internally, I resisted it. I didn’t want to stay on the surface like a duck—I wanted to dive.

But that mindset has completely changed.

Today, I see swimming for what it truly is: a world of its own. A space of depth, precision, and endless tools to explore. More than that, it’s a gateway to becoming a more complete human being. Swimming is one of those fundamental modes of movement that I truly believe every person benefits from mastering—on many levels.

Especially for freediving, it opens an entirely new dimension. Learning to feel the water through each stroke, the angle of the hand, the pressure on the forearm, the connection through the whole body, the streamline is incredibly refined. It’s a level of detail and awareness I never imagined existed. And once you start to understand it, everything in the water begins to change.

Here are some of the reasons why swimming has become a central part of my life design for health and becoming a better athlete in freediving:

1. Train Without a Safety Buddy

One of the biggest limitations in freediving training is safety. Freediving in all its shapes requires a trained buddy. Swimming training, however, allows you to train breath control, technique, and conditioning safely without needing a safety diver every session. Of course, proper safety awareness is always essential, especially when integrating breath-hold elements. But compared to full freediving sessions, the logistical barrier is significantly lower. This means you can train more consistently—and consistency is what ultimately builds performance.

2. Less Equipment

Freediving training can sometimes involve a lot of gear.. Buoy systems, lines, weights, wetsuits, long fins. In contrast, pool training can be refreshingly simple.

Most sessions require nothing more than goggles—sometimes short fins, a pull buoy, or paddles. Letting go of the wetsuit, weights, and long fins already brings a sense of ease and freedom, making training far more accessible—especially when it’s combined with a workday or fitted into a busy schedule. This simplicity makes it much easier to stay consistent, even while traveling or during demanding weeks. There is just no excuse, you can always go!

3. You Train the Exact Muscles You Need for Freediving

Swimming allows for highly specific conditioning for all freediving disciplines.

Whether you’re working on no-fin dives, bi-fins, monofin, or even FIM (Free Immersion), the pool offers endless opportunities to refine your movement.

Many movement patterns and muscle chains can be trained effectively in the water. Even with short fins, you can build almost everything you need. If your pool doesn’t allow long fins, don’t get frustrated—it makes sense. Long fins, and especially the monofin, can be dangerous in crowded lanes when awareness and experience are lacking.

Instead, use what’s available and train smart.

For example:

• Dolphin kick drills to build monofin basics and develop a natural feel for water flow

• Arm stroke drills for improving on no fin technique, making it so much more efficient and bulding up confidence

• Streamline and glide-focused work to improve CNF efficiency, refining both kicks and arm movements

Combined with gym training, swimming helps translate strength into efficient, purposeful movement—where freediving performance truly happens. You want to train your muscle to only move the part that is needed!

For freedivers, this means your muscles learn to work exactly where they’re needed—with minimal wasted energy.

4. CO₂ Tolerance & Highly Efficient Training

One of the most powerful aspects of swim training for freedivers is the ability to train CO₂ tolerance dynamically. CO₂ tolerance plays a key role in breath-hold performance because the urge to breathe is primarily triggered by rising carbon dioxide levels rather than falling oxygen levels. And a CO2 tolerance is built not only phsyically but also through awareness and nervous system regulation with a lot of repetitions and finding ease in discomfort in the water.

Research on breath-hold divers shows that experienced divers often have higher tolerance to elevated CO₂ levels, which allows them to remain calm and efficient during apnea (Schagatay, 2011).

In the pool, you can train this with many variations:

• reduced breathing patterns (e.g., breathing every 5–7 strokes) on semi long distances

• repetitions of apnea sprints

• FRC (Functional Residual Capacity) short dives in combination with swimming but without weight that adds to the training and improves your overall feeling in the water

• strength endurance sets with limited breathing

These sessions can become extremely demanding, sometimes to the point where you crawl out of the pool completely exhausted. But this is exactly where the adaptation happens: your body learns to tolerate high CO₂ levels while staying relaxed and efficient.

Pool training allows you to combine multiple performance elements in one session:

• cardiovascular conditioning

• breath control

• technique work

• muscular endurance

• mental focus

  
  

Compared to deep diving sessions, where long recovery times are required between dives, swimming allows for high training density and structured intervals. This kind of interval training is well studied in sports science and is known to improve both aerobic capacity and muscular efficiency (Laursen & Jenkins, 2002). For freedivers, this means more adaptations in less time.

5. You Can Train Even When Injured

Another major advantage is flexibility. Even when dealing with minor injuries or physical limitations, swimming allows you to adapt training without stopping completely.

Examples:

• leg-only drills with a kickboard

• arm-only swimming with a pull buoy

• technique drills with reduced load

• breath work during easy swimming

• This keeps you connected to the water and maintains training continuity, which is crucial for long-term performance.

6. The Advantage of Swimming Science

Swimming is one of the most scientifically studied sports in the world.

Over decades, researchers and coaches have developed:

• advanced training methodologies

• technical drills

• biomechanical analyses

• conditioning systems

Freediving, by comparison, is still a relatively young sport. By borrowing knowledge from swimming science, freedivers can benefit from well-tested training approaches that accelerate development.

Two Years of Swim-Based Training

I have been training like this for almost two years now. And I feel the impact in every freediving discipline. Swimming created a stable physical and mental foundation that supports everything I do underwater.

No Excuses

If you don’t have the right dive buddy,

if your local pool does not allow monofins,

or if deep diving is not always accessible,

with injury,

practicing movement in the water is always possible!

And it might be one of the most powerful tools you have to become a better freediver—over time. Building this foundation takes patience and conscious, consistent training. Don’t expect results after just one swimming session. You need a plan, regular practice, and—most importantly—joy in the process. When your training is enjoyable, progress comes naturally, and the foundation you build will support everything you do in the water.

References

Schagatay, E. (2011). Predicting performance in competitive apnea diving. Part III: deep diving. Diving and Hyperbaric Medicine.

Toussaint, H. M., & Truijens, M. (2005). Biomechanical aspects of peak performance in human swimming. Animal Biology.

Laursen, P. B., & Jenkins, D. G. (2002). The scientific basis for high-intensity interval training. Sports Medicine.