If you've ever watched a group of swimmers at a meet and noticed mysterious numbers scrawled up their arms in Sharpie, you've seen arm marking in action. It looks a little funny, but it's one of the most practical things you can do to help your swimmer get to the right place at the right time.
Coaches do their best, but they're managing a dozen (or thirty) kids at once. Announcements over the PA system are borderline impossible to hear when you're in a humid natatorium with 200 screaming families. And let's be honest — asking a 9-year-old to remember four event numbers, heats, and lanes from a brief team meeting is a big ask.
That's why we mark arms.
What You're Writing
The goal is to give your swimmer a quick-reference cheat sheet on their body. For each event, they need three pieces of information:
- E — Event number
- H — Heat number
- L — Lane number
Most parents set this up as a simple grid on the inside of the forearm. It looks something like this:
| E | H | L | Event |
|---|---|---|---|
| 23 | 3 | 4 | 50 Fr |
| 27 | 2 | 6 | 100 IM |
| 31 | 5 | 3 | 50 Bk |
| 38 | 1 | 2 | 50 Fly |
That's it. Four events, written small enough to fit on a forearm, big enough for your kid to read while standing behind the blocks.
The Right Marker (This Matters)
Use a Sharpie or permanent marker. Not a ballpoint pen. Not a gel pen. Not a felt-tip marker from the art bin.
Your swimmer is going to be in and out of the water all day. Anything that isn't permanent ink will be a smudged mess within an hour. A fine-point Sharpie works great — it's precise enough to write small and holds up through chlorine, sweat, and the inevitable arm-rubbing that happens when kids are bored between events.
Some parents swear by the ultra-fine point Sharpie for neater handwriting. Either way, bring a spare. You'll probably end up marking a teammate's arm too.
Where to Write
The inside of the forearm is the standard spot. It's easy for the swimmer to read (they just flip their arm over), and it's somewhat protected from rubbing against things.
Start near the wrist and work your way up toward the elbow. If your swimmer has a lot of events (looking at you, 8 & Under swimmers doing six events), you've got plenty of forearm real estate.
A few things to keep in mind about placement:
- Write on clean, dry skin. If they've already applied sunscreen, wipe the area with rubbing alcohol first or the ink won't stick.
- For outdoor meets, apply sunscreen after marking, not before.
- Some teams have their own conventions about which arm to use or how to format the grid. Check with your coach before your first meet.
Walking Through an Example
Let's say your swimmer, Emma, is entered in four events at Saturday's meet. You've checked the heat sheet and found:
- Event 12 — 50 Free, Heat 3, Lane 5
- Event 18 — 100 IM, Heat 2, Lane 3
- Event 24 — 50 Back, Heat 4, Lane 6
- Event 30 — 50 Fly, Heat 1, Lane 2
Here's what you'd write on Emma's arm:
| E | H | L | Event |
|---|---|---|---|
| 12 | 3 | 5 | 50 Fr |
| 18 | 2 | 3 | 100 IM |
| 24 | 4 | 6 | 50 Bk |
| 30 | 1 | 2 | 50 Fly |
Write the column headers (E, H, L) at the top so it's clear what each number means. Adding the event name at the end of each row — like "50 Fr" or "100 IM" — helps younger swimmers who might mix up their event numbers. When they hear "50 Freestyle" announced, they can scan their arm for the matching row instead of trying to remember which event number goes with which stroke.
If Emma has a relay event, you can note that too, but relay specifics (like which leg she's swimming) are usually handled by the coach at the meet.
When to Mark
The night before is ideal for outdoor meets. Your swimmer's skin is clean and dry, you're not rushed, and it gives the ink time to fully set. For indoor meets, morning-of works fine — just do it before you leave the house, not in the car (trust me on this one, the handwriting in a moving car is never good).
If the markings fade or smudge during the meet, just touch them up. That spare Sharpie in your bag is going to come in handy.
Getting the Info Without the Hassle
The annoying part of arm marking isn't the actual writing — it's finding all your swimmer's events in the heat sheet first. You're flipping through pages of tiny text looking for your kid's name, jotting down event, heat, and lane on a scrap of paper, and hoping you didn't miss one.
SwimDeets generates a printable marking guide from your uploaded heat sheet. It pulls out your swimmer's events in order with all the E/H/L info you need, so you can just read it off and write. It's a small thing, but it saves you from that "wait, was it Heat 3 or Heat 4?" second-guessing.
Removal Tips
After the meet, your swimmer is going to have faded Sharpie on their arm that soap and water won't fully remove. Here are a few tricks:
- Rubbing alcohol works the best. Put some on a cotton ball and wipe.
- Hand sanitizer (the alcohol-based kind) also works in a pinch.
- Baby oil or coconut oil can break down the ink if you don't have alcohol handy.
- Or just let it fade. It'll be gone in 2-3 days. Some kids wear their arm markings to school on Monday like a badge of honor.
A Few More Tips
- Double-check your work against the heat sheet. Transposing a number is easy, and swimming in the wrong lane can lead to a disqualification.
- If your meet offers a backup copy of the heat sheet at the check-in table, grab one. Plans can change if there are scratches (swimmers who don't show up), and sometimes heats get re-seeded.
- Let older swimmers mark themselves. By 11 or 12, most kids want to do it on their own. Hand them the Sharpie and the info — it's a good step toward meet independence.
- Some teams use temporary tattoo paper to print event info. It's a cool option if you want to get fancy, but a Sharpie works just as well.
Arm marking is one of those swim parent rituals that feels weird the first time and totally normal by meet three. Your swimmer will start holding out their arm automatically, and you'll have the Sharpie ready before they even ask.