Watch water resistance: understanding ATM and meter ratings
Understanding water resistance: ATM, meters, WR
"30m WR", "10 ATM", "100 meters"... These figures do not mean you can dive to that depth with your watch. This guide explains everything about watch water resistance.
ATM / Meters / Usage equivalence table
| Indication | Authorized use |
|---|---|
| 3 ATM / 30m WR | Rain, light splashes only |
| 5 ATM / 50m WR | Sink, rain, no swimming |
| 10 ATM / 100m WR | Swimming, snorkeling |
| 20 ATM / 200m WR | Sport diving, snorkeling |
| 30 ATM / 300m WR | Professional diving |
Why "30m WR" does not mean diving to 30m?
Standards are tested under static conditions. Wrist movements create pressure shocks that multiply the actual pressure. This is why a "30m" watch should not be worn for swimming.
Water resistance of our Seiko Mods
All Seiko Prestige Seiko Mods are guaranteed 10 ATM / 100 meters. You can wear them in the shower, in the pool, and for snorkeling.
How to preserve water resistance
- Never manipulate the crown underwater
- Rinse with fresh water after salt water
- Have seals checked every 2-3 years
Water resistance FAQ
Can I wear my Seiko Mod to the beach?
Yes, our 10 ATM watches are perfectly resistant to seawater. Rinse it with fresh water afterward.
Is condensation under the crystal a problem?
Yes, it is a sign that the water resistance is compromised. Contact us — covered by the 2-year warranty.