What is the speed advantage of a wetsuit?

Everyone knows wetsuits help keep you warm in cold water. Lesser known among the general public (but well-known among triathletes) is that wetsuits also make you swim faster! The buoyant neoprene in a wetsuit floats a swimmer higher in the water, decreasing drag and thus increasing swim speed.

But how much faster is a wetsuit? I’ve heard various rules of thumb: 10% speed increase; 4-6 seconds per 100m; 1 minute per kilometer. I’ve also heard various caveats: it depends on the swimmer’s skill (better swimmers benefit less); it depends on the swimmer’s body-type (naturally floaty people benefit less); it depends on the quality of the wetsuit (you get what you pay for); it depends on the fit of the wetsuit; and so forth.

So the answer is: It depends. Because I’m usually disinclined to let things go at “it depends,” I decided to conduct a field experiment. Reef & Run, which I’ve written about previously, provided the perfect laboratory. Almost every Thursday evening between June 21 and yesterday, August 23, I swam one mile in the ocean at East Beach in Santa Barbara. Two weeks were canceled because of shark sightings, and one week I was sick – leaving a sample of 7 swims.

The swim took place at the same time each Thursday: 6:30pm. The conditions were generally similar: low-mid 60s water temp; winds out of the W or SW, producing moderate surface chop and a W-to-E current (i.e., head current going out, tail current coming back). I would characterize them as “rough water conditions” – the view in the above photo is typical. The course was identical each week – a full mile (1609 meters) measured with GPS, and marked by permanently installed buoys.

Generally, I had done a full workout earlier in the day, plus one lap of the course as warm-up. So, for each of these races I was warmed-up but perhaps a touch fatigued. In any case – pretty close to an ideal setup for my field experiment.

My wetsuit is a cheap-o XTERRA Vortex sleeveless, which frankly doesn’t fit me very well. So – a conservative test of the wetsuit effect. Presumably, I would be even faster in a high-end, well-fitting, full-body wetsuit.

Me in the orange cap. Three-time Olympic water polo player Wolf Wigo at left. The two others in the photo were doing a different race. Photo by Mike Eliason, Santa Barbara News-Press

Of the seven races, I wore a wetsuit for four of them and went “naked” for three of them.

My wetsuit-assisted times were: 19:52*, 20:02, 20:14, and 20:14.

My “naked” times were: 21:36, 21:37, and 21:41.

* For the purpose of this analysis, I’m throwing out the 19:52 wetsuit-assisted time. That was the season opener, and it was different in several respects: gorgeous, flat conditions; bigger, more competitive field (thus more drafting opportunities). I’m not surprised I was substantially faster that week.

That leaves a sample of six times – three wetsuit-assisted and three “naked.” My average wetsuit time was 20:10, with a range of 12 seconds. My average “naked” time was 21:38, with a range of 5 seconds.

So, according to my field experiment, my personal “wetsuit effect” – even with an ill-fitting cheap-o sleeveless – was 1 minute, 28 seconds in an open-water mile. That converts to 5.5 seconds per 100m, or a speed effect of 7.3%.

Any other self-experimenters out there? Please leave your data in the comments!

32 thoughts on “What is the speed advantage of a wetsuit?”

  1. Evan, thanks for taking the time to collect this data. I find it very convincing despite what might normally be called a small sample size 😉 Come on, you didn’t want to swim a few hundred miles for more validity?!? (kidding)

    Your times cluster well and show a clear repeatable gap. Pretty much perfect statistically. I haven’t ever done repeated mile swims like this, just 100yd repeats, but my experience and other triathlete/swimmer experience all supports your data.

    A 7.5% speed boost from equipment is enormous and can’t be ignored. This really supports your argument that results must be separated and/or swims held with distinct, sensible rules. To win a wetsuit-legal race, a swimmer must wear a wetsuit.

    Also, you’re pretty dang fast.

    1. Thanks, John. My results were remarkably close to what I expected. Based on previous racing (in the same wetsuit) I had an intuitive sense that it made a difference of about a minute per 1K, and 90 seconds per mile. And like I said, my wetsuit’s not even a very good one.

      For what it’s worth (although I never did any testing) my sense is that the full-body textile “tech suits” formerly allowed in pool swimming made a difference of about 2 seconds/100. Maybe a little less than half the effect of a wetsuit – but still a substantial effect!

  2. Three years ago I swam 5 two-mile open water lake swims on the same course in fairly uniformly calm conditions. I swam two with the same sort of ‘farmer john’ suit, one with a Blue 70 rubber tri suit (designed for no-wetsuit triathlons) and my race jammers. I alternated the wetsuit and jammer races, with the Blue 70 race being in the middle. The two wetsuit race times were in the 40 minute range, the Blue 70 race was 42-something and the jammer times were 44-something. So, this is consistent with the wetsuit conferring substantial speed in freshwater OW swims.

  3. John Hughes, If that was the swim series at Grant Ranch I remember that. I couldn’t touch ya in the wetsuit, I could draft you a while in the Blue 70 but you pulled away towards the end of two miles and in jammers we were are more typical neck and neck.

  4. One other effect I’ve noticed while swimming with wetsuited swimmers, is that wetsuits don’t give the same speed increase when swimming into chop/ wind. Probably because you’re a bit higher in the water and more susceptible to interference from the conditions? The corollorary is true too, when swimming with chop and prevailing wind, you get a little bit extra push when wearing a suit.

  5. Evan, Just came across your article. Interesting because I just completed a test with my new triathlon wetsuit (Orca Equipe) yesterday. Bought two weeks ago, and after competing last year in Triathlons without a wetsuit and finishing towards the back of the pack, decided to invest in a new suit.
    Here are my results and yes I was very surprised. Completed (2x 500m) swims at my local swim pool over 2 consecutive weeks(4 in total). Averaged 12min 30sec without suit and 10min 35sec with the suit on. Not tired after swim with suit.

  6. I’ll second your findings, they are what I concluded after testing wet suits a couple years ago. I’ve only every tested my wetsuit in the pool as I’ve deemed OW events to have to many variables – thought yours swims cluster incredibly closely together, particular since drafting was also in the mix.

    In the pool I tested a quality suit and a middle of the rangel suit (both full suits) and found very little difference between the two (however I didn’t text extensively). Over 4 1k TT’s each a week apart I went 13:57 (naked) 13:10 (Wetsuit (Quality), 14:11 (naked), 13:14 (wetsuit (Middle). The 13:57 was a PB at the time and I’ve always felt It was a standout swim when compared to the others. For that reason I tend to air on the side of the 14:11 time and concluded that its approx. 6 sec per 100m + (for triathletes) the benefit of being less fatigued after. Not exactly a huge sample size but it was enough data for me to swim away happily (hate wearing the suit in the pool so I was keen to not repeat it).

    I’ve surmised that there may be another 1-2 secs per 100 in it for OW swimming as the temperature of OW is far more conducive to swimming hard than overheating in a pool. I also feel that for triathletes that are not working maximally in the swim the benefit a wetsuit has is probably 1 sec greater than comparing maximal efforts with and without suit – but that’s just a thought. In theory I think wetsuits allow you to hold pace better and therefore more benefits over greater distances… but in reality the longer the distance between buoys in OW means more off course adventures so it probably negates itself. Maybe one day I’ll do a 4k TT in the pool with a wetsuit to compare to my naked ones but I’m not sold on trying this anytime soon.

    I read prior to this test in a published paper that wetsuits were worth 8 seconds per 100 for average swimmers, 5 for good swimmers and 2 for elite swimmers. I think their definition of average swimmer is probably better than what I’d call average but its still valid. Elite = Olympic.

    All of my findings, the article and your findings appear to confirm one another.

    1. Ryan – very interesting analysis! Thanks for sharing. I think with both of our experiments there are some sample size issues… but food for thought nonetheless.

      1. I’m just curious/concerned about how much warmer my zero-percent body fat brother is than I am with a wetsuit (just in average). Poor guy was blue and violently shivering without one today, even ten minutes after the Mike. I was fine “naked”, no shivering at all. Doing the three tomorrow, he can’t hang w/o the wetsuit. So how much will it help him? Btw, nice times on those swims!

        1. Sorry, I’m not following your question. For example, not sure what “ten minutes after the Mike” means.

  7. Thanks for this. I know some people test wetsuits in the pool to see which suit is fastest for them. This article was helpful to me because I am thinking about doing a sprint tri, which has a “half mile” swim, which in my experience means anything from 500 yards to 1000 yards. Based on the tests people mention, I am thinking I will go without a wetsuit, seeing as I am very slow at getting my wetsuit off. If I gain 45 seconds by wearing it, but it takes 30-60 seconds to take it off, there’s not much benefit.

  8. I have to wonder if you included your transition times in your report above. I think in all fairness to accuracy, you must do that. You will take extra seconds or a minute to remove the wetsuit in transition. That speed gain you made? Is it lost struggling to remove the suit? Can you include your times for the races above to demonstrate the real time gain using a wet suit?

    1. I just did a triathlon without a wet suit and was very slow and noticed that many others with wet suits had a faster transition time. My theory is that any time gained by not having to remove a wet suit is lost by the fact that it is extremely exhausting swimming in an open lake without a wet suit, hence the slower transition time. I consider myself extremely well conditioned for combat sports and will be investing in a wet suit.

  9. I am not a strong swimmer, have 3 sprint triathlons and an Olympic under my belt. In the Olympic i finished 63 of 63 in the swim, 37 in the bike and 11 in the run, good for 30 overall. Give you that only to give you perspective on my swim ability.

    After a sprint tri with 58 degree water and no wetsuit last year, I decided a wetsuit would be a good investment. Bought a low end sleeveless wetsuit. Have only done 2 workouts in the suit, but results have been consistent.

    Typically, i swim 2:11 to 2:15 per 100 yards as measured by my Garmin Swim watch In a pool. Workout #1 in wetsuit was 2:00 per 100 yard average and workout #2 was 1:59 average. And, to echo an earlier post, I was not nearly as tired after the wetsuit workouts. The 1:59 time was actually immediately after an upper body weightlifting session so I was already somewhat fatigued.

    I really feel that as I get more comfortable in the suit, I can push a little harder and drop anther 3-4 seconds per 100.

    So, for me at least, the wetsuit results In a significant advantage of at least 10-12 seconds per 100 yards.

  10. Hi Evan,
    thanks for the very-informative article!
    I have a question, what about the thickness of the suit? I believe the thicker (e.g. 5mm vs 1mm) the more effect is might have on the speed?
    I currently have a 5mm (long sleeves), and I’m thinking of buying a sleeveless wetsuit, as in summer I might be faster without sleeves… but I don’t know how thin I should go, or whether to stick to 4-5mm.
    Ana (WI, Michigan Lake)

    1. Hi Ana – yes, a thicker wetsuit would have a greater flotation effect, which theoretically would make you faster. Sleeved wetsuits will almost always be faster than sleeveless, though sleeveless may be more comfortable (less constricting).

      Personally, I don’t wear wetsuits because I hate them.

      Good luck!

  11. This has been my ‘BIG’ question…to wear one or not. After reading this great information, it does put my mind to rest, so thank you for your time and analysis. One thing to consider is also your transition time from swim to bike. How much time do you take when taking your wetsuit off vs if you were to wear an outfit that you can wear for the whole race. Time to take off suit vs time saved in transition zone by not wearing one, is it worth it then? That could be another analysis test… 🙂

    1. Hi Claire – that’s a good point about the transition time (though I don’t do tris). From what I understand most experienced triathletes are fairly efficient in getting out of their suits.

  12. Great article! If anyone out there is repeating this type of test it, would be interesting to see heart rate data as well (if there are heart rate monitors that work in water and horizontal orientation, mine doesn’t). It’s one thing to save time, and another to save effort and not to spike your heart rate at the beginning of a triathlon during the swim. I’m a reasonably good swimmer, and my general rules for wetsuit vs no wetsuit are: Sprint triathlons – no, unless the water is 73 (time benefits outweigh the transition time lost at this distance); half irons – yes, unless the water is warm (I’m also a heat wimp). One thing that people forget about when it comes to wetsuits is temperature. Swimming in warm water with a wetsuit will make your core temperature skyrocket, followed by your heart rate. Thus, time benefits are probably negated by energy costs in warm water.

    1. Very good point about the energy costs of wetsuits in warm water, potentially offsetting the buoyancy/efficiency advantage!

Leave a Reply

Your email address will not be published.