According to Wikipedia and to CONI:

Some part of the swimmer must break the surface of the water throughout the race, except it shall be permissible for the swimmer to be completely submerged during the turn and for a distance of not more than 15 meters after the start and each turn. By that point the head must have broken the surface

I fail to see the point of this rule, it seems completely arbitrary to me.

While arbitrary rules are usual in heavily regulated sports, this strikes me as quite odd in a "freestyle" environment...

Why does freestyle swimming restrict underwater swimming?

  • FYI, without the question, this sounds like a rant.
    – user527
    Commented Jul 30, 2013 at 17:47
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    Just making things crystal clear. Sports SE had a question that was being interpreted as asking for health/medical advice because the OP said "stick doctor."
    – user527
    Commented Jul 30, 2013 at 17:52
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    Maybe they don't want these situations: youtube.com/watch?v=Vox9KOxC1ZA
    – Bernhard
    Commented Jul 31, 2013 at 11:05
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    @Bernhard yes but the question is why do they want to avoid such situations? "freestyle" is supposed to be, as the name implies, as free as possible, and innovation should be encouraged…
    – o0'.
    Commented Jul 31, 2013 at 11:09
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    @waxeagle why? It's actually free except for this single rule, and that's why I'm wondering why this rules exists at all.
    – o0'.
    Commented Jul 31, 2013 at 13:40

4 Answers 4


Ultimately this goes back to David Berkoff, a US Olympic backstroker in the '88 and '92 games. He realized that by dolphin kicking underwater he could go faster than swimming on top of the water (no surface tension to slow you down). Using this technique, he was able to set several world records and an NCAA championship.
The problem was, this underwater dolphin kick is also quite suitable for freestyle or butterfly, and if most of the race is underwater dolphin kicks there wouldn't be much difference between the strokes. (Breaststroke requirements preclude dolphin kicking). Therefore FINA decided to limit the distance that a back/fly/free swimmer could remain underwater dolphin kicking. Why 15 meters was chosen isn't completely clear, other than being a manageable fraction of a 50 meter long course pool, and not to far off what many people were doing already coming off a wall with a few kicks. At least one note I have found states the original limit was 10 meters (Source: Berkoff's bio at the International Swimming Hall of Fame site).

  • I think this should be the right answer. As a long-time swimmer myself I think it's important that each stroke is different and without the underwater restriction there would be nothing separating fly, backstroke or freestyle. In the context of swimming, "freestyle" isn't really meaning "get to the other end using any means possible", it simply means you can use any of the 4 established strokes to complete the race. Commented Mar 21, 2018 at 16:17
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    @WillAppleby - actually, 'freestyle' has two different meanings. For non-medley (relay or IM), it means anything other than back/breast/fly. By itself (any 'freestyle' event) it can mean anything you want, including dog paddle, sidestroke, corkscrew, ... - anything at all. Freestyle is not defined in the rulebook like back/breast/fly. You use a forward start, must breakout by 15 meters, must touch the wall, and must finish by touching the wall. That is all (except, again, it can't be back/breast/fly in a medley event).
    – Jon Custer
    Commented Mar 21, 2018 at 16:37
  • If that was the reason they could have restricted the underwater swimming only in the non-freestyle events. Freestyle should not have any style restrictions… Commented May 26, 2021 at 21:26

When you allow someone to complete their entire swim as a glide you do a few things that are not considered good for the sport

  • You emphasize swimsuit technology over strength and speed
  • Emphasizes lung capacity over strength and speed
  • Don't use half the body

Swimming is a total body sport about strength and speed. If you allow someone to go the whole way under water you change the competition into something that it's not intended to be.


My guess is that the 15 m line was chosen because it is the least multiple of 5 m that will not force most swimmers to surface unnaturally early after the start. Had they picked 10 m, half of us would break the rule by just doing what used to be normal. Of course, by introducing the rule they also made most of us strive to reach further than before. A 50 back or 50 fly in short course is not much swimming anymore. And the same swimmer can excel in both events by just having a great kick in a way you just couldn't in the days when swimmers swam more in these events.

As for why freestyle is not free to be done totally submerged, it basically goes back to the origins of the sport. It was always done on the surface (sub-surface swimming, with mono fins and snorkels for example, is governed by a different organisation) and when flip turns were invented, no one thought about restricting the under water part of the turn because everyone returned to the surface soon enough to breathe anyway. The backstroke events at the Seoul olympics changed that. And when the rule was introduced for backstroke, it was also introduced for butterfly and freestyle to avoid the same thing happening there.

As an aside, backstroke is pretty much as free as freestyle. You just cannot chose to swim it on your stomach like you can in freestyle.

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    Do you have any sources for this? The question does state "at worst, interviews/articles from informed experts...".
    – Nij
    Commented Jul 21, 2016 at 3:22

As with just about any sports activity, part of the answer boils down to money. If nobody watches, there's no money. And, if 95% of a swim race were to happen underwater, as it would if this rule didn't exist, even fewer people would watch swimming than already do.

While the Olympics are nominally an "amateur" event, they have become pretty much like all other televised sports events and, sadly, that means money is a factor. Since the Olympics are probably THE most watched swimming contests in the world, they tend to dictate the rules that everyone else follows.

Sort of like when the Indy 500 effectively banned turbine engines back in the 70s by limiting the size of the intake so much that no turbine could function. If that rule hadn't been implemented, everybody would have run turbine engines starting in 1968. Same in swimming - if this resurfacing rule didn't exist, everybody would just swim entire laps under water using the fish kick. Not much fun to watch. . .

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    When an existing answer already explains the origin of the rule, a new answer based on speculation that doesn't match it is not likely to be valid.
    – Nij
    Commented Mar 9, 2018 at 5:35
  • I'm going to remind everyone to please Be Nice - that includes both content and tone. Thank you.
    – Philip Kendall
    Commented Mar 12, 2018 at 13:17

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