Can You Run in Speedos? Or Do A Triathlon Shirtless!

Speedos are actually a brand name. They’re better known as trunks or swim briefs. They’re common in the sports world – they’re used for swimming, water polo, and diving. Running shorts that look remarkably similar to Speedos are also a common sight in high-level running, particularly for women.

Speedos are designed to swim in. The spandex or lycra construction of the triangular front and solid back conforms closely to the contours of your body making them both comfortable and fast in the water.

So, can you run in Speedos? While it is possible to run in Speedos, however, people find it very uncomfortable. Regular Speedos are not designed for running, but one can buy specially designed running briefs which, whilst they look the same as Speedos, are far more comfortable. They’re more breathable, made from moisture-wicking fabric, and are designed not to chafe.

Can I Wear a Speedo for A Triathlon?

Speedos were only designed to swim in. Whilst they are brilliant for the swim section of the triathlon, it also means they leave a lot to be desired on the other two legs of the triathlon.

If you’re entering triathlon from a swimming background, it may seem natural to ask if you can enter a triathlon wearing what you’re used to swimming in – Speedos. Or if you’re new to triathlon, wearing a pair of Speedos may seem like a perfectly natural choice. After all, you’ve seen people swimming in them at the highest level. So you know you can swim in them – but what about the rest of the race?

Remember that the swim is less than the third of the competition!

Bike shorts have a thick layer of internal padding between your legs, running right up to the top of your groin. Speedos don’t have this padding. On the bike, that lack of padding will make you really uncomfortable.

Also, check out What to Wear & Not Wear Under Swim Trunks ?

This will be a problem, especially when you’re trying to maintain your aero position.

The pressure on your groin will be large, and the padding is needed to relieve it – without any padding, it will be more difficult to maintain your aero position in a pair of Speedos.

Many short-distance runners run in what looks like Speedos. However, Speedos aren’t suitable for longer distances, so on the run leg of your triathlon, Speedos will naturally ride up into your groin because of the constant leg movement.

That means they’ll bunch and then rub the joint of your leg and groin, which can be incredibly painful. It won’t just be painful, however; if you’re on the run leg it’s likely you will already be tired so your Speedos running up will be an irritation you don’t need.

However, if you’re looking to race shorter triathlon distances, such as sprint or super sprint, a padded short isn’t mandatory.

Many triathletes do race these shorter distances in briefs; however, they rarely use Speedos. They tend to use running briefs, which are more comfortable, dry quicker and don’t bunch up into your groin when your leg is moving forwards and backward, as it will on the bike and run.

Of course, the ideal clothing for a triathlon is a tri suit or at least tri shorts. For more on this check out our post Do You Change Clothes During a Triathlon? Your Options of What To Wear!

Also, if you’re doing a triathlon in warm conditions, Speedos won’t give you much protection against the sun; this can lead to overheating, as well as potential sun damage to your skin.

In colder conditions, Speedos won’t cover enough of your skin to provide warmth. Going from the swim to the bike can be a big issue, as the wind chill can really amplify the coldness of the water to create what feels like a layer of ice on your skin!

Can You Swim in Sport Shorts?

While it is possible to swim in sports shorts it is counterproductive as they will slow down the swimmer as a result of poor hydrodynamics. A large amount of loose material means that the shorts have a larger surface area; this means an increase in friction, which in turn means that the swimmer has to work harder to overcome the drag.

As well, sports shorts aren’t comfortable to swim in. They don’t offer any support when you are swimming, which can make it quite uncomfortable. Sports shorts also tend to have a looser waistband; if you’re swimming with a strong current, the current can get inside the waistband. This can not only increase drag, it could even pull the shorts down!

For more on this, check out our post titled “Can You Wear Running / Exercise Shorts For Swimming & Triathlons?

If you’re training, the best thing to swim in is jammers. These are not only designed to be close-fitting and hydrodynamic, they are also designed to prevent damage from chlorine. This is especially important if you’re doing most of your training in the pool. Finally, they do offer some compression, which helps increase circulation. (Source)

Can You Run Shirtless in A Triathlon?

There are many triathletes who chose to run without a shirt, and there are certainly some benefits to ditching a top, however, there are several triathlon organizers that prohibit participants from going shirtless on the cycling and running legs.

If you’re deciding between wearing a two-piece triathlon suit for your race or going shirtless, then running shitless will probably have an advantage; two-piece tops tend to fit looser than triathlon suits, which means there is more drag.

In warmer races, running shirtless can cool you down; whilst materials have been developed that wick away sweat really well, if you’re competing in an environment as warm as California or the Middle East, even the best top is unlikely to be able to wick away all the sweat you’ll generate. That leaves you with an uncomfortable shirt that is wet through with sweat and clinging to your body. In this situation, running shirtless is a great alternative that will prove far more comfortable.

Some triathlons may have rules about competing shirtless. This may be due to factors like temperature, or factors about the locality. If you’re running through a residential area, people may not want hundreds of shirtless people running past their windows all day! It’s best to check the rules before you decide to run shirtless; they should be sent to you before you race, but if you can’t find them, try calling or emailing the race organizer. (Source)

What Do You Wear During a Triathlon?

The best thing to wear in a triathlon is a proper, dedicated specifically designed triathlon suit. The first benefit is that the triathlon suit is designed to do all three sports in succession, so you won’t have to change between legs, or be uncomfortable when doing any of them.

Check out How Much Does a Triathlon Suit Cost? Options, alternatives, and what to look for

However, triathlon suits do have an upper body section. In fact, the suit relies on being suspended over your shoulders in order to stay up.

That means if you’re looking to run shirtless, they may fall down! If you want to run shirtless, the best alternative would be triathlon shorts, which are tight padded lycra shorts help up by a drawstring. They are essentially the bottom half of a triathlon suit, so they offer the tightness needed for the swim, the padding needed for the bike and the movement and comfort you need in the run.

When you’re choosing what to wear in a triathlon, you may be worried about how you look.

Don’t be. No triathlon clothing makes you look great; it is the same for everyone. But that’s fine – nobody chooses to do triathlons to look cool. We do them to push ourselves. You should pick the clothing that is going to bring out the best in you – that means either what you’re most comfortable or fastest in. Nothing else matters.


An extreme triathlete who have competed in dozens of triathlons including IronMans and Extreme triathlons.

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