Triathlon Race Body Marking And Identification Methods: Complete Guide

I love the body marking ritual. It is a cool part of any race, and honestly, I like to flash it to other people even when it is over. I’m sure many triathletes are with me on this one!

However, bragging right is not the only reason for body marking. Body marking is a ritual in triathlon to help identify participants in a race. There is one main reason why officials assign body numbers, and that is identification! Some triathlon races can have up to a thousand participants coming with their equipment and bikes, and keeping everything organized without race identification methods would be a nightmare for organizers.

To avoid mix-ups that may occur with large crowds, or for officials to quickly see your number, Triathletes are given a number that can be written on their arms and legs. Some races provide a sticker for your bike, helmet, tri suit while assigning body marking for the swim course.

On a good side note, check out my Best Triathlon Battle-Tested Budgeting Gear for a smooth triathlon experience

Many triathletes have complained about working themselves to the ground before they can remove the marker. So, what exactly is being used for these body markings?

In most races, a regular permanent marker or temporary tattoo sticker is used! Body marking and tattoo are all parts of the race identification process and in accordance to a USAT rule state that “Participants shall plainly display their race numbers at all times, and shall maintain the race number in an unaltered, unobstructed and readable state at the start and finish gates, in the transition areas, and on the course. Any violation of this Section shall result in a variable time penalty.” (Source).

Let’s dive deep into the methods of identification in the triathlon race and why this is needed, but first, consider checking out How Do Triathletes Go To The Bathroom While Racing? Tips and Tricks

What is race identification?

Before we move on to the tools used to write on triathlete skin, let address race identification. Newbies may be wondering what this is and why it is relevant in triathlon.

What is race identification? They are marks or numbers given to the participant on race day to help officials identify a participant at any point during the race. While this is according to the rule, it is understandable that each race is different, while the final decision on the identification process employed is left to the race official.

Race Identification practice includes:

Body marking and tattoo

Body marking and tattoos involve writing the triathlete’s race and numbers in a specific location on the body. It helps to easily identify any triathlete in case of medical emergencies. Markings and tattoos are essential for the swim course since water can reduce the adhesiveness of race stickers.

Since the rule requires that triathletes’ numbers be visible throughout the race, markings can serve as a failsafe throughout other legs and not only in the swim course.

Body markings are supposed to be visible but maybe covered up by a wetsuit or compression clothing. However, this problem can be rectified if the markings or tattoos are placed at strategic points.

For instance, if a triathlete is wearing an armband, the body marking should be placed above or below the armband such that it is visible at all times. Also, the arm should be prioritized over the leg when placing a body mark or tattoo.

Race bib identification

Race bibs are the most commonly used means of identification in many triathlon events. Also known as run bibs, a triathlete usually wears them in the run leg of any USAT sanctioned race.

According to the rules, these race bibs have to be visible at all times ( except in the swim leg), either the front, back, or sides.

Losing the race bib can incur a variable time penalty. Check our post on the triathlon rules and the most common violations

Bike Rack identification

A bike rack sticker is a simple and effective way of identifying your rack stand. This practice has proven effective and prevent mix-ups because it helps athletes identify their spot within the transition area.

But note that some races use open racking, which does not require these racking stickers.

Officials should consider the size, space, and number size when ordering these stickers as it will help athletes easily identify their bikes when they enter the transition area. Note that adhering the sticker to a wet rack may cause the adhesive to fail.


A wristband is another form of race identification that is effective, especially if there are different races within one event. It allows an athlete to access race areas that are closed-off to the public.

What is better is when race directors can imprint athletes’ numbers on the wrist band making it easier to match athletes to bikes for checkout for security measures.

Race bands are better utilized when different races are occurring within an event. Having a wristband with different colors can easily take care of such situations.

Bike helmet and frame identification

Bike helmets and frame identification are incredibly beneficial to both officials and triathletes alike.

Triathlon Helmet Number
Triathlon Bike frame identification

Swim cap and Swim course identification

The swim cap and swim course identification are why the body marking, and the tattoo was invented in triathlon. Having a visible race number makes identification easier in case of medical emergencies.

It benefits athletes in terms of safety and boosts the effectiveness of the medical team. Race identification in swim serves three purpose

  1. Accountability
  2. To boost the medical team’s effectiveness
  3. It improves the integrity of the race and makes it easier to award penalties to offenders

What You can use to Write on your Body in a Triathlon

Now you understand why race identification is important; It saves both the athlete and official a lot of stress and allows the two parties to carry on effectively.

Generally, permanent markers are used for body markings, while some use art markers for race tattoos.

 Using ordinary permanent markers is a bit dangerous as they can contain toxic and harmful chemicals. Also, any marker that would be used for markings should be sweat and waterproof; however, there have been complaints from athletes about having difficulties removing these marks after a race.

Here are some good brands for body marking and tattoo

  • Sportsafe marker
  • Sharpie
  • Mark sport
  • Bic temporary tattoo marker

What is the chemical composition of a Body Marker?

The composition of the body marker determines whether it is toxic or not due to the chemicals used in its production.  Below are the general chemical composition of a body marker, although these may vary according to different manufacturers(source);

  • N-butanol
  • Diacetone Alcohol
  • Xylene
  • N-propanol
  • Cresol

Some of these chemicals are mildly toxic; however, prolonged exposure to them may be quite damaging. Chemicals can enter the bloodstream through broken skin, so you may not be aware that you are exposing yourself to dangerous chemicals. However, markers labeled skin safe or non-toxic are safe to use.

Why do I Need Body Marking?

From the triathlete perspective, body marking allows photographers to easily associate the photos with the participants so that they can easily pick them out as one whole package rather than having to browse endless number of photos.

Body marking is can also come in handy if you misplace your race chip and were not picked up by the sensors . It makes it easier for officials to identify you and rectify the issue.

Is Body Marking Dangerous?

No, it is not; however, writing with a regular or industrial marker may be. Some of the regular ones contain toxic chemicals that may be injurious to health. So the next time you want to use a marker during an event, make sure it is body-safe or non-toxic.

Where do Officials Mark in the Body?

Since body marking must be visible at all times, officials usually mark your upper arms and may opt to mark your back of both leg calves.

If the triathlete is wearing an armband, the body markings are placed above or below it such that it is always visible.

And if the triathlete is wearing compression socks, it is placed on the quadriceps above the socks and below the tri suit.

You should check out the article on what to wear for a triathlon race; everything you need to know!

Wrong Ways of Marking and Tattooing the Body

There is a right and wrong way of applying it (source). Below are some of the wrong ways of writing a tattoo

  1. If the numbers are upside down or backward; then it is not well written.
  2. If it is missing some numbers, this is why it is crucial to give the officials the proper digit.
  3. If it is applied on the outside of the arm such that it is not visible unless the triathlete turns.

How to Remove Body Marking and Tattoos in Triathlon

Triathletes often complain about how difficult it is to remove body markings after race day; some even call for banning this ritual. Nevertheless, there are simple and effective ways to remove body markings;

  1. You can scrub in the shower. If this did not work out then;
  2. Moisten the area with alcohol or baby oil. Wipe off with cotton wool soaked in alcohol. Rinse with clean water and repeat the process until the mark has completely disappeared.

On a side note, also check out How To Avoid Chafing And Blisters In Triathlons? Prevention & Treatment Tips

Final Thoughts

Race identification is an essential practice that aids officials in their jobs and encourages faster response in case of medical emergencies. Body marking and tattoos are a race identification practice that allows officials to award numbers to triathletes and photographers to easily compile images for each participant.

While body marking is fantastic, race officials need to use skin-safe markers for triathletes. You don’t have to get worked up to cleaning the markers; there are simple and effective ways to do so.  


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

Recent Posts