Watch water resistance ratings explained
What 30 m, 50 m, 100 m and 200 m really mean, when it is safe to swim, and how to keep a watch water resistant.
What the ratings mean in practice
The metres are a pressure test in a lab, not a depth you can safely reach.
- 30 m (3 bar): splashes and rain. Not for swimming.
- 50 m (5 bar): brief swimming at most, depending on the brand.
- 100 m (10 bar): swimming and snorkelling.
- 200 m and up, or marked "diver": swimming and recreational diving.
Keeping it water resistant
- Make sure a screw-down crown is screwed fully down before water.
- Never operate the crown or pushers underwater unless the watch is rated for it.
- Avoid hot showers and saunas. Heat ages the gaskets.
- Have the water resistance tested every year or two, and after any battery change or case opening.