Sports Books Release Tokyo Olympic Swimming Odds

Disclaimer: SwimSwam and its authors do not directly endorse betting on swimming. This is intended to strictly be an informative and entertainment article. Online and sports gambling carry financial risk. Players should be aware of this risk, and govern themselves accordingly. 


  • Thursday, July 22 – Sunday, August 8, 2021
  • Swimming: Saturday, July 24 – Sunday, August 1, 2021
  • Tokyo, Japan

We are less than two weeks away from the Tokyo Olympics, and that means we get to discuss something that is rarely available to aquatic sports fans: gambling on swimming.  While the swimming betting scene is microscopic compared to major sports like basketball, soccer, or football, it is much more robust than in 2016, as the betting options for swim fans in many countries–particularly the United States–have changed substantially since the 2016 Olympic Games.

During the last Olympic cycle, Nevada was the only state where sports gambling was legal, leaving residents in other states either better through illegal bookmakers or overseas websites. Today, sports betting is available in nearly half of the United States (as well as Washington D.C. and Puerto Rico), with measures passed in an additional roughly 10 states to enable sports gambling in the coming months or years. We should note, however, that sports betting is restricted to in-person wagers only in many of these states, including Delaware, New Mexico, and Arkansas.

For the sake of this article, we will use American odds (also known as “moneyline odds”) and their implied probabilities. American odds show favorites lead with a minus (-) sign, indicating the amount you need to bet to win $100. For example, Evgeny Rylov is a -250 favorite in the men’s 200 backstroke, meaning you would need to stake $250 to win $100. The implied probability is just a way to represent the implied likelihood that wager hits.

The implied probability equation for negative odds is as follows:
[absolute value of negative American odds] / ([absolute value of negative American odds] + 100) * 100

… yielding an implied probability for a Rylov win at 71.4%:
250 / (250+100) * 100 = 71.4

Odds for underdogs or tightly-contested events will be accompanied by a positive (+) sign, indicating the amount you would take home for every $100 you wager. Continuing our men’s 200 backstroke example, defending Olympic champion Ryan Murphy is listed at +275, implying you would win $275 on a bet of $100.

The implied probability equation for positive odds is as follows:
100 / ([absolute value of positive American odds] + 100) * 100

… yielding an implied probability for a Murphy win at 26.7%:
100 / (275+100) * 100 = 26.7

Three things to note:

  1. The larger the positive number, the bigger an underdog perceived by bettors and the bookmaker
  2. In both cases above and all numbers referenced below, if you win, you get your initial wager back, in addition to the amount won
  3. The summation of implied probabilities will always be more than 100% if you convert each athlete’s listed odds in a particular event. We won’t dive too far into it, other than to say that this is where the house gets its edge (or “vig”)

There are numerous online sports gambling websites that will take Olympic swimming wagers, but for today, we will just mention two that have a robust set of available betting options: DraftKings (based in the U.S.) and Pinnacle (based in Curaçao). In some cases, the odds vary substantially, likely due to the bookmaker balancing its lines based on how the public is wagering. Here are some findings from the available odds:

Men’s Findings

  • Of all wagers across DraftKings and Pinnacle for both men and women, Adam Peaty in the 100 breaststroke is (unsurprisingly) perceived as the closest thing to a “lock”. He is listed as a whopping -2000 favorite (95.2% implied probability of winning)) on DraftKings and -2646 favorite (96.4%) on Pinnacle.
  • World record holder Kristof Milak is the next largest favorite we could find, at -1600 (94.1% implied probability) on DraftKings and -800 (88.9%) on Pinnacle in the 200 butterfly
  • Caeleb Dressel is favored in all three of his individual events, including hefty odds in the 50 free (-900 on DraftKings, -963 on Pinnacle) and 100 fly (-1148 on Pinnacle, unavailable on DraftKings). Those 50 free and 100 fly odds all have an implied probability of greater than 90%
  • In the 50 freestyle, 2012 Olympic champion and 2016 silver medalist Florent Manaudou is listed at just +4000 on DraftKings, and is not even listed on Pinnacle as an athlete you can wager on
  • Michael Andrew is the gold medal favorite in the 200 IM, at an even-money +100 on DraftKings and +105 on Pinnacle (roughly 50% implied probability). Daiya Seto has the closest odds at +275 and +193 on the two respective sites
  • Seto is favored in the men’s 400 IM at -105 and -168 odds on DraftKings and Pinnacle
  • Evgeny Rylov is listed as the favorite in both backstroke events, even with defending champion and world record holder Ryan Murphy in the field. Rylov is listed at +140 and -250 in the 100 and 200 backstrokes on DraftKings, while Murphy is listed at +275 for both events. Given his lifetime bests and how comfortable Murphy looked at Trials, these odds in particular made us do a double-take
  • There are no relay bets available on DraftKings, but Pinnacle has posted odds:
    • 400 freestyle relay: U.S. is favored at -341 (77.3% implied probability), with Russia next at +174 (36.5% implied probability)
    • 800 freestyle relay: Australia (+111; 47.4% implied probability) and Great Britain (+228; 30.5% implied probability) have the shortest odds in the field
    • 400 medley relay: U.S. is favored at -397, with Russia next at +448

Women’s Findings 

  • Ariane Titmus is a strong favorite over Katie Ledecky in both the women’s 200 and 400 freestyles over. In the 200, Titmus is listed as a -344 favorite (77.5%[!!!!] implied probability), with Ledecky coming in at +380 (20.8% implied probability). In the 400, Pinnacle lists Titmus as a -293 favorite, while Ledecky is a +187 underdog
  • Ledecky is favored in the women’s 800 (-365) and 1500 freestyles (-424)
  • Kaylee McKeown is favored in both backstroke events. In what will likely be a tight battle between world record holders with Regan Smith in the 100, McKeown is listed  at -145 and -111 on DraftKings and Pinnacle, respectively.  Smith is listed at +150 on DraftKings and +211 on Pinnacle
  • Fellow Aussie Emma McKeon is the favorite in the 100 freestyle at -110 (DraftKings) and -113 (Pinnacle) Countrymate Cate Campbell has the second shortest odds at +250 (DraftKings) and +295 (Pinnacle). McKeon and Campbell are also gold/silver favorites in the 50 freestyle
  • Lilly King is an overwhelming favorite in the 100 breaststroke at -347 on Pinnacle. DraftKings does not list odds for the event
  • Similar to the men, there are no relay bets available on DraftKings, but Pinnacle has posted odds:
    • 400 freestyle relay: Australia is unsurprisingly a heavy favorite at -1350 (93.1% implied probability). Team USA is next at +486 (17.1% implied probability)
    • 800 freestyle relay: Australia (-500) is again an overwhelming favorite, with the U.S. at +300
    • 400 medley relay: U.S. is favored at -250, with Australia next at +200

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Awsi Dooger
2 years ago

Great summary by the OP including description of the odds. I lived in Las Vegas for 24 years as a sports bettor. I also worked as sportsbook supervisor at the joint taking the biggest action in town at the time. Don’t kid yourself. There is no such thing as inside information. Nothing is fixed to help the house. The sportsbooks are life and death to have employees show up on time and have the same number on the betting board as in the computer. It is all about power ratings. If the sportsbooks have reliable power ratings they are confident in their numbers and are willing to risk. But in sports without power ratings they are tentative and petrified. The… Read more »

Last edited 2 years ago by Awsi Dooger
Reply to  Awsi Dooger
2 years ago

Do you see any other value bets for various events?

2 years ago

Imagine betting Katie Ledecky will win the 1500 or the 800.

Reply to  Seth
2 years ago

Who’s gonna beat her, you?

Reply to  Seth
2 years ago

I am looking to bet against her if she has a bad 400. Its not that I don’t think she will win its just that the odds will be quite juicy

2 years ago

anyone know if BetMGM is making a book on swimming yet?

2 years ago

Three long odds I like on FanDuel are Haughey +2900 in the 200 free, Sjostrom +1000 in the 100 free, and Manuel +1400 in the 50 free.

I think all three are too realistic to be such big underdogs. Sjostrom was arm wrestling on Insta yesterday, her elbow is fine. Manuel is a gamer and every day that passes she’s farther and farther away from the time she took off. Those odds are just pure disrespect to Haughey.

Reply to  Willswim
2 years ago

Since I think Titmus is probably going to win anyway I’m not sure it makes sense to bet on Haughey. I agree those odds are completely unfair to her though.

Reply to  Willswim
2 years ago

Manuel is the bet I’d take of those 3.

Reply to  Willswim
2 years ago

I put $5 on Taylor Ruck at +10000 in the 100 Back and then must have started dreaming of how I’d spend the winnings in my head because I completely missed Dawson. +1600 is too juicy to pass up, I’ll go back and throw $5 or $10 on her too. Thanks!

2 years ago

The Over / Under for WR – 5 1/2

Reply to  Stephen
2 years ago

I think I’d take the under, just because I don’t trust things coming out of COVID.

5 1/2 is a good number, though. That’s about where I’d set it too I think.

Mixed medley relay is almost a given, so we start with 1!

Reply to  Braden Keith
2 years ago

we will know a lot after the first couple of nights… w100 fly, m100 br, w400 fr, w4x100, I could all see going down, though that is not to say I think all will. But if we have two of those go down I would take the over, and if dressel pops a 47.0 lead off on m4x100 then I think theres a good chance he gets all three of his since he tends to get faster through the meet

Reply to  Braden Keith
2 years ago

Morning finals has me questioning how fast overall these olympics will be.
On the surface, 5 1/2 is a low number. Considering the Aussie ladies could be involved in 3 relay WR

Reply to  Stephen
2 years ago

I’d take over because it is likely that the Men’s 50 free, 100 free, 100 fly, 100 breast, maybe even 200 breast/200 fly are likely/could go down. This doesn’t even account for relays or women’s events where it is likely more records could go down

2 years ago

As it was correctly mentioned in the article “the swimming betting scene is microscopic”. It means that number of people who are gambling on results of swimming events is not big. It means that practically same people who participate on swimming websites’ chatting boards are trying their luck by gambling. Yes, they are risking their money, instead of saying irresponsibly “read my lips” or “you hear this first here”, but it doesn’t mean they have more information. Simply in addition of being “talkers” they are becoming “easy money gamblers”.
The Sports Books in swimming events have same predictive quality as Swimswam’s predictions of outcome of American Olympic Trials.
If the betting scene is huge like in the case… Read more »

2 years ago

I endorse betting on swimming. Just keep the wagers to what you can afford. I am going to do a bunch of parlays and the other thing I am looking to do is make a few wagers based off how people swim the first day or two of the meet.

2 years ago

Ryan Murphy is my MORTAL LOCK

About Morgan Priestley

Morgan Priestley

A Stanford University and Birmingham, Michigan native, Morgan Priestley started writing for SwimSwam in February 2013 on a whim, and is loving that his tendency to follow and over-analyze swim results can finally be put to good use. Morgan swam competitively for 15+ years, primarily excelling in the mid-distance freestyles. While …

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