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Why Is Open Water Swimming Slower Than Pool Swimming?


Open water swimming is typically slower than pool swimming due to the lack of controlled conditions. In open water, factors like waves, currents, cold temperatures, and the need for constant sighting disrupt your rhythm. Additionally, there are no walls to push off, and visibility is often limited, making it harder to maintain speed compared to a pool environment.


I know how it feels to be doing so well in the pool, hitting paces based purely on perception. Then, I head into the lake, feeling great, only to look at my watch and realise I’m much slower than I thought.


What Are The Differences Between Pool and Open Water Swimming?

The most glaring difference between pool and open water swimming is the environment itself. Pools offer clean, still water, marked lanes, and walls to kick off from. In contrast, open water introduces waves, currents, plants, and sometimes even wildlife that can interfere with your swim. Add to this the absence of a black line to follow, and you’re faced with the constant challenge of sighting, which can disrupt your stroke.

A open water swim course. With low lighting and turn buoys all around.

Swimming in open water is less predictable and, therefore, slower. The controlled conditions of the pool allow for a more consistent rhythm, but in open water, maintaining that rhythm requires adapting to ever-changing surroundings. For example, I’ve noticed that my threshold pace in the pool is around 1:20 per 100m, while in open water, it tends to drop to around 1:27-1:30. This doesn’t sound like much, but it can add up over a long swim, especially during races.


Preparing for Open Water After Pool Training

Transitioning from pool training to open water requires more than just physical preparation—it demands mental readiness too. Pool swimmers often find the lack of visibility and walls, unpredictable water conditions, and the vastness of open water disorienting at first.


Make sure you have a well-fitting wet suit and goggles with good clarity. Set your expectations that you might not be swimming in a straight line, and you might feel like you’re making less forward progress than expected.


Adapting Your Stroke for Open Water

Your stroke needs to be adaptable. In the pool, the long, smooth stroke you’ve perfected works well because there’s little external disruption. You can kick a lot and maintain good balance. But in open water, you might need to adjust. Waves, wind, and other swimmers can interfere with your rhythm. Shortening your stroke slightly and increasing your stroke rate can help you maintain speed and keep momentum, especially in choppy conditions.


In my coaching, I always recommend increasing your stroke rate and reducing your leg kick when swimming in open water. Without the opportunity to rest your legs on push-offs, conserving energy through a more efficient stroke is key to keeping pace over long distances.



A man sighting low in the water while swimming front crawl


Sighting Techniques and Pitfalls

In open water, sighting becomes one of the most critical skills. Unlike pool swimming, where you have the luxury of a black line guiding you, open water swimming requires you to look up frequently to stay on course. However, poor sighting technique can easily slow you down. Lifting your head too often breaks your rhythm and compromises your body position, creating unnecessary drag.


I always tell my athletes to lift only their eyes above the surface when sighting. This keeps your hips higher, reduces drag, and minimises the strain on your lower back. Remember to sight first, then rotate to breathe—this helps maintain smoother momentum without compromising your body position. The image above is a good example.



Cold Temperatures and Swimming Speed

Swimming in cold water can be a shock to your system. Colder temperatures tighten muscles, limit your range of motion, and increase fatigue, which naturally slows you down. It also burns more energy as your body works harder to stay warm, making endurance an even greater challenge.


The first time I swam in open water, it was 13 degrees. I had a wet suit on and was probably the strongest swimmer in the group, but after 100 meters, I had to stop. The cold water shock made breathing really difficult, and it took a moment to compose myself before I could continue. It was a pretty scary experience, especially since I couldn’t stand up in the deep water.


Always warm up before getting into the water to ensure your muscles are ready and not starting cold. A great tip I learned from another triathlete was to pour cold water down your wet suit before starting, so the cold isn’t as shocking when you first hit the water. Cold water conditions require extra mental and physical preparation, and wearing a well-fitted wet suit can help regulate body temperature and improve performance.


A group of cold swimmers in the water with wetsuits on


Wetsuit Advantages and Disadvantages

Wetsuits offer both benefits and potential drawbacks in open water. The added buoyancy can help lift your legs, reducing drag and making it easier to maintain a streamlined position. However, not all wetsuits are designed for every swimmer. If your wetsuit is too tight, it can restrict your range of movement, making your stroke technique suffer. Although wetsuit tech has improved greatly in recent years, there is always a trade-off between buoyancy and flexibility.


The Open Water Environment

The open water environment can vary drastically, and this variability is one of the main reasons swimmers are slower compared to pool conditions. Waves, currents, wind, and temperature all impact your swim. Even something as simple as weeds or reeds can slow you down by dragging at your arms or legs.


During one triathlon, the water was so full of weeds that I ended up pulling myself along using them because it was more efficient than swimming through them! You have to adapt quickly to these kinds of unexpected challenges, which can slow your overall time.


Darkness and Limited Visibility

Poor visibility, whether due to murky water or low light, can be intimidating. It forces you to rely more on your sighting and navigation skills. Without the familiar walls or lane lines of a pool, staying on course becomes more difficult, which can easily slow you down.


I tend to swim in dark lakes, where I can’t see the bottom. Occasionally, I get the thought, "I wonder what’s down there." Thankfully, the worst I’ve encountered is a harmless fish nibbling someone’s toe. Nevertheless, this mental distraction can still impact your focus and performance.


No Walls to Push Off

One of the biggest speed advantages pool swimmers have is the ability to push off the walls after every turn. These powerful push-offs give you a boost that can shave time off your lengths. In open water, there are no walls to rely on, meaning you have to maintain consistent effort throughout the swim.


Without walls, every stroke counts. This requires greater endurance and a solid pacing strategy, as there are no breaks or speed boosts to rely on.


Turning and Drafting in Open Water

2 people swimming in a harbour navigating around boats.

Turns in open water are more complex than in the pool. Navigating around buoys without losing speed is a skill that takes practice. Poorly executed turns can cost you valuable time and momentum, so practicing your turns in race-like conditions is crucial.


I always race into swim turns and finishes to avoid getting caught up in any melees. This allows me to maintain my momentum and avoid getting tangled up with other swimmers, which could easily slow me down.


In one local event this year, I started further back, caught up to the leaders, and drafted behind them for the second half of the swim to conserve energy. By keeping my stroke rate up and staying close behind the lead, I was able to finish strong without tiring too quickly.


Staying Calm in Open Water

Open water can be overwhelming, especially for those new to it. Without the structure of a pool, it’s easy to feel anxious. Staying calm is critical, as panic can lead to inefficient strokes, increased heart rate, and wasted energy.


The more regularly you expose yourself to open water conditions, the more comfortable and confident you’ll feel. Over time, you’ll learn to stay focused even when conditions get tough.


How Your Mental State Affects Your Swimming Pace

Your mental state can have an impact on your swim speed. Anxiety, fear of the unknown, or even frustration from being slower than expected can slow you down. On the flip side, being too relaxed can lead to a drop in effort. The key is maintaining a balance between focus and calm. I know all too well how you can relax too much in open water, without the need to focus on the upcoming wall!


Mental toughness is just as important as physical endurance in open water. Staying present, focused, and confident can help you push through the challenges that open water brings.


Safety Considerations for Open Water Swimming

While open water swimming offers a rewarding experience, it also comes with inherent risks that shouldn't be overlooked. Unlike pool swimming, where every risk is assessed, open water can be unpredictable. Strong currents, cold temperatures, and even marine life pose potential hazards. Always take caution and check for any warning signs before entering the water.


Open water safety ring

Make sure to swim in designated areas, use common sense, and never swim alone—especially in unfamiliar waters. Wearing a brightly coloured swim cap, using a swim buoy, and letting someone know your where you are are simple precautions that can make all the difference. Open water swimming can be exhilarating, but safety should always be your top priority.


Why is Open Water Swimming Slower?

Open water swimming is generally slower than pool swimming due to a variety of unpredictable factors. Unlike the controlled environment of a pool, open water introduces waves, currents, and temperature fluctuations that can disrupt your rhythm. The absence of walls to push off and limited visibility further complicate maintaining speed.

Adapting your stroke, mastering sighting techniques, and conserving energy with a higher stroke rate can help mitigate these challenges. However, the variability of open water—from the conditions to the mental demands—makes it inherently more difficult to swim as quickly as in a pool.


For these reasons, open water swimming is often slower, but with practice, many of these obstacles can be managed to improve performance.


Always prioritise safety by staying aware of the risks, from cold water shock to unseen hazards, and take precautions before each swim.


 

About the Author:

The author of the post, Chris Searle

Chris Searle is a Level 3 Qualified British Swimming Coach and a Level 2 British Triathlon Coach, also holding various running and cycling coaching qualifications.


With over 14 years of experience coaching athletes of all levels, Chris has developed British Champions in swimming and guided triathletes to podium finishes on the world stage.


You can read more about Chris's coaching journey on the About page.

 

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