Watch Water Resistance Explained: What 3 ATM, 5 ATM and 10 ATM Really Mean
By Robert · · 4 min read
"Is my watch waterproof?" is one of the most common questions we get. The honest answer is that no watch is truly waterproof. Watches are water resistant to a certain level, and that level is printed as a number in ATM, bar or metres. This guide explains what 3 ATM, 5 ATM, 10 ATM and 20 ATM really mean, what you can safely do with each, and how to keep your watch protected.
If your watch has already let water in, see our watch repairs service in Nairobi for water resistance testing and resealing.
What Does ATM Mean on a Watch?
ATM stands for atmospheres, a unit of pressure. 1 ATM is roughly the pressure of 10 metres of still water. So:
- 3 ATM = 3 bar = 30 m
- 5 ATM = 5 bar = 50 m
- 10 ATM = 10 bar = 100 m
- 20 ATM = 20 bar = 200 m
ATM, bar and metres are three ways of writing the same rating. A watch marked "30M" and one marked "3 ATM" have the same water resistance.
Why 30 Metres Does Not Mean You Can Dive to 30 Metres
This is where most people get caught out. The rating comes from a static pressure test in a lab, with the watch perfectly still. In real life, moving your arm through water, diving in, a strong shower jet or a sudden temperature change all put extra pressure on the seals. That is why a watch rated 30 m is not suitable for swimming, even in a shallow pool.
What You Can Do at Each Rating
| Rating | Hand washing and rain | Shower | Swimming | Snorkelling | Diving |
|---|---|---|---|---|---|
| 3 ATM / 30 m | Yes | No | No | No | No |
| 5 ATM / 50 m | Yes | Not recommended | Light swimming only | No | No |
| 10 ATM / 100 m | Yes | Not recommended | Yes | Yes | No |
| 20 ATM / 200 m | Yes | Not recommended | Yes | Yes | Recreational diving |
We advise against showering with any watch, whatever its rating. Hot water and soap can soften the seals over time, and steam can fog the glass from the inside.
What About Our Watches?
Most fashion and business watches, including the models we stock from Binbond, Curren, Naviforce, Chenxi, Skmei and Poedagar, are rated 3 ATM (30 m). That covers:
- washing your hands and face
- rain on the way to work
- sweat and the odd splash
They are not made for swimming, the shower, the sea or the pool. Examples include the Naviforce 9095, the Skmei 1816 and the Curren 9113, all rated 3 ATM.
A diver look is not a dive rating. The Poedagar 682 has a rotating diver-style bezel, but it is rated 3 ATM. Always go by the rating, not the style.
What About Smartwatches and "IP" Ratings?
Smartwatches often use IP ratings instead. The D68 Smartwatch, for example, is IP67, which means it is dust-tight and can survive brief accidental immersion. It is still not a swimming watch. Our smartwatch price guide has more on choosing one.
"Waterproof" on a Listing
You will sometimes see the word "waterproof" on watch listings and boxes, including some budget models. Treat it as meaning "water resistant" and check the actual rating. If no rating is given, keep the watch away from water.
7 Ways to Protect Your Watch from Water
- Push the crown fully in (and screw it down if it screws) before your hands go near water.
- Never press buttons underwater. Pushers on chronographs and digital watches let water in when pressed.
- Take it off before swimming, showering, the sauna or a hot tub.
- Keep leather straps dry. Water stains and weakens leather. Switch to a metal or silicone strap if you are often around water.
- Rinse after salt water with fresh water if it gets splashed at the coast, then dry it.
- Avoid sudden temperature changes, such as going from hot sun straight into cold water.
- Retest after any repair. Opening the case for a battery change can disturb the seals.
Water Resistance Wears Out
The rubber gaskets that keep water out dry and harden with age, heat and cosmetics. A watch that was water resistant when new may not be after a few years. If you see fog or droplets under the glass, take the watch off and bring it in straight away. Moisture inside rusts the movement quickly.
Our watch repairs service offers pressure testing and gasket reseals. If you have recently had a battery changed elsewhere, read our guide to watch battery replacement in Nairobi to know what a proper job includes. For other faults, see 8 common watch problems and how to fix them.
Need Help?
Not sure what your watch can handle? Contact us with the model, or browse our executive watches collection and check the rating on each listing.
