WATCH BASICS
Watch water resistance, explained
The number on the dial isn’t the depth you can dive to — it’s a lab pressure rating, and the real-world advice is more cautious. Here’s exactly what 30m, 50m, 100m and 200m let you do, the myths that ruin watches, and how to keep yours sealed.
What each rating really means
30m
3 ATM
OK: Everyday splashes, rain, hand-washing.
Avoid: Do NOT swim, shower or submerge.
50m
5 ATM
OK: Splashes and brief, shallow contact.
Avoid: Not for swimming or diving.
100m
10 ATM
OK: Swimming and snorkeling.
Avoid: Not for scuba diving.
200m
20 ATM
OK: Swimming, snorkeling, recreational scuba.
Avoid: Check for a dive (ISO 6425) rating for serious diving.
300m+
30 ATM+
OK: Scuba and saturation diving (true dive watches).
Four things that quietly kill water resistance
- • Hot water & steam — showers, saunas and hot tubs expand the case and gaskets. Keep watches out of the heat.
- • Operating the crown or pushers underwater — never do it, and always screw the crown down before contact with water.
- • Age — rubber gaskets dry out and shrink. Water resistance is not permanent and should be re-tested periodically.
- • After a battery change or service — the case was opened, so insist on a fresh pressure test before you swim.
When to service
Keep seals fresh & tested.
Watch glossary
ISO 6425, ATM, and more.
Track your watches
Log service & pressure tests.
Frequently asked questions
Can I swim with a 30m (3 ATM) watch?
No. A 30m rating is meant only for incidental contact with water — rain, splashes and hand-washing. Despite the number, it is not designed for swimming or submersion. You generally want at least 100m (10 ATM) to swim comfortably.
What does ATM mean on a watch?
ATM stands for atmospheres of pressure. 1 ATM is roughly the pressure of 10 metres of water, so a 10 ATM watch is rated to 100m. The rating is tested under static laboratory pressure, not real-world swimming, which is why the practical guidance is more conservative than the number suggests.
Can I shower or bathe with my watch?
It’s best not to. Hot water and steam can cause the metal and gaskets to expand and degrade, and soap can damage seals. Even a highly water-resistant watch is better kept away from hot showers, saunas and hot tubs.
Why can’t I swim with a 50m watch?
Water-resistance ratings are measured under static pressure, but swimming adds dynamic pressure from arm movement that can briefly exceed the rating. As a rule of thumb, 50m handles splashes, 100m handles swimming, and 200m+ handles diving.
Do I need to do anything before getting a watch wet?
Yes — always make sure the crown is fully pushed in (and screwed down, if it screws), and never operate the crown or pushers underwater. Have the water resistance re-tested every couple of years, especially after a battery change or service, because gaskets wear out.
Does water resistance last forever?
No. The rubber gaskets that seal a watch age, dry out and compress over time, so water resistance degrades. If you regularly get a watch wet, have the seals checked and pressure-tested during its normal service, and log it in the Veloce service log so you know when it was last verified.
Log when your seals were last tested
Keep a service history with pressure-test dates for every watch, free in the Veloce app.