Water resistance explained: what 30, 50, 100 and 200 m really mean

The “100 m” on a dial does not mean you can take the watch 100 metres down. It refers to a static laboratory pressure test. Moving your arm in a pool adds pressure the test does not. Here is the honest translation.

Three things that void any rating

1. Operating the crown underwater. Pulling the crown out opens the case. Set the time on dry land. On our dive models, screw the crown back down every time.
2. Hot water. Showers, hot tubs and saunas expand the seals and pull moisture in as the watch cools. Take it off.
3. Old seals. Rubber gaskets dry out. A pressure test proves the seals were good on the day of the test; it does not guarantee them for years. Have the seals checked every 2–3 years if you swim with the watch, and after any battery change.

What we do before shipping

Every watch is pressure-tested to its rated depth before it leaves Seattle. If a watch fogs up under the crystal within the warranty period and you have not opened the case, that is covered — see what the warranty covers.

Leather straps and water

The case can be water resistant while the strap is not. Leather that gets wet repeatedly will stiffen and smell. If you swim with a 100 m watch, put it on the rubber or steel strap first.