The Triathlete Blueprint Newsletter #105-Swim Smarter: Get the Most Out of Drafting for Free Speed

Yan Busset
May 3
4 min read

Read time: 4min.

By Coach Yan Busset

Swim Smarter: How Drafting Can Save You Seconds in Open Water

In triathlon, drafting on the bike isn’t allowed in long-distance races, but in the swim, it is. So you might as well use it, and use it well, because it can make a big difference. Either you save a lot of energy, or you swim faster for the same effort.

In this article, we’ll look at why you should draft, what the science says, where to position yourself to get the most benefit, how much time you can actually gain, and how to train this skill properly before race day.

Why you should draft

Just like cyclists in a peloton or birds flying in formation, drafting in swimming helps you move forward more efficiently by reducing the resistance caused by water. It’s not just a marginal gain. It’s a real performance factor.

Most triathletes are aware of drafting, but very few train it consistently or understand how powerful it really is when done correctly.

What the science says

The study by Chatard and Wilson (2003) tested drafting positions behind and beside a lead swimmer being towed in a streamlined posture. The results showed a clear benefit.

Drafting reduced the swimmer’s metabolic cost by 11 to 38 percent at closer distances (0 to 50 cm behind). Even further back, at 100 to 150 cm, the energy savings were still between 8 and 31 percent. Side drafting, with the drafter’s head near the leader’s hip, provided only about a third of the benefit compared to drafting directly behind.

And since the lead swimmer in the study wasn’t even kicking or stroking, it’s reasonable to assume the effect could be even more beneficial in real open water race conditions with more turbulence.

Where is the best place to draft?

To get the most out of drafting, position yourself directly behind the feet of the swimmer in front, at a distance of around 20 to 50 cm. That’s where the water is most disturbed and where drag is lowest.

If you’re further back, around one to one and a half meters, you still get some benefit but it’s reduced. Side drafting can be useful in certain situations, especially in crowded starts or when you want to avoid direct contact, but the effect is smaller.

Avoid swimming too close and tapping their feet constantly, as it breaks your rhythm and theirs. Finding the sweet spot takes awareness and practice.

How much time can you gain?

Based on the 3 to 6 percent speed improvement seen in the study, here’s what drafting can save depending on your swim pace:

Pace (no drafting)	Drafting pace (approx.)	Gain per 100 m
1:15 / 100 m	1:11.5 to 1:13	2 to 3.5 sec
1:20 / 100 m	1:15.5 to 1:17.5	2.5 to 4.5 sec
1:30 / 100 m	1:25.5 to 1:27	3 to 4.5 sec
1:40 / 100 m	1:34 to 1:36	4 to 6 sec
2:00 / 100 m	1:53 to 1:56	4 to 7 sec

And projected over real race distances:

Pace (no drafting)	Gain over 1500 m	Gain over 3800 m (Ironman)
1:15 / 100 m	30 to 52 sec	76 to 133 sec
1:20 / 100 m	37 to 67 sec	95 to 171 sec
1:30 / 100 m	45 to 68 sec	114 to 171 sec
1:40 / 100 m	60 to 90 sec	152 to 228 sec
2:00 / 100 m	90 to 105 sec	228 to 266 sec

These are real gains. For many athletes, that’s the difference between exiting the water with a stronger group or swimming alone for the rest of the race, also these time gain estimation can help you to seed yourself in the right group if your race has a rolling start.

A fun fact about drafting

Did you know that the swimmer you're drafting can benefit too?

It turns out that having someone close behind can slightly reduce the drag acting on the back of the lead swimmer. The water pressure around both swimmers changes, and resistance decreases a little bit for the leader. It’s not a big advantage, but it’s real. Drafting doesn’t just help the follower. It gives something back to the leader too.

Don’t improvise on race day

Drafting well is a skill. You can’t expect to discover it on race day. You need to practice it beforehand with someone else, ideally in a group. The closer and smoother you can swim behind someone, the more benefit you’ll get.

You can also practice drafting in the pool. Create a pace line with your training group. Take turns leading. Or swim in pairs with one swimmer just behind the other. Like cycling, rotating leads is a great way to train both roles.

And a quick reminder. Don’t blindly trust the swimmer you're drafting on race day. They might swim off course. Always sight occasionally to make sure you're still heading in the right direction. Gaining four minutes means nothing if you swim 200 meters extra.

Drafting is one of the easiest ways to swim faster and save energy on race day. And yet, most triathletes don’t take full advantage of it. Just remember, it’s not something to improvise. Train it with others. Get used to swimming close. Practice sighting while drafting.

In triathlon, free speed is rare. This is one of the few times you get it. Use it.

Thanks for reading. If you found this helpful, feel free to share it with your training group or triathlon buddies, especially the ones who always swim solo.

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