Watch water resistance explained: what 3, 5, 10 and 20 bar mean

A water rating is the pressure a new watch withstood in a test, and everyday use should stay well below it. In practice, 3 bar (30 m) covers rain and hand-washing, 5 bar (50 m) covers a shower and a short swim, 10 bar (100 m) covers swimming and snorkelling, and 20 bar (200 m) is where watches built for diving start.

Last checked 1 November 2026. This is the scale we use on every product page; the standards behind it are listed at the end.

The scale at a glance

Rating Also printed as Fine for Not for Our watches
3 bar 3 ATM, 30 m, 30M Rain, splashes, washing your hands Showers, baths, swimming 33 of 55
5 bar 5 ATM, 50 m A shower, a short swim at the surface Snorkelling, diving 14
10 bar 10 ATM, 100 m Swimming, snorkelling Scuba diving 7
20 bar 20 ATM, 200 m Swimming, recreational diving if the watch is built for it Saturation diving 1

Bar and ATM are units of pressure, and for a watch rating they mean the same thing. One bar is roughly the pressure of 10 metres of water, which is where the metre figures come from. A dial that says "30M" and a spec sheet that says "3 bar" are describing the same rating.

Why "30 m" doesn't mean 30 metres

The standard for everyday water-resistant watches, ISO 22810:2010, sets the tests a watch must pass before its maker may print a rating on it. The test is done on a new watch with fresh seals, held still in water, often on a sample from the production run rather than every piece. Wikipedia's summary of the standards says a depth rating does not mean the watch was designed for repeated long-term use at that depth.

Real wear is harder on a watch than the test. Wikipedia lists what decides whether a watch survives: the age of the seals, past damage, temperature and mechanical stress. Moving through the water adds a little pressure too. Wikipedia gives fast swimming as roughly equal to five extra metres. So the number on the dial is a ceiling for a new watch, and each band in the table above sits well below it.

3 bar (30 m): rain and hand-washing only

Most of our watches sit here, including every CURREN, POEDAGAR and OLEVS we sell. A 3 bar watch will survive rain, washing up and a splash, and that's all. Take it off before a shower, a bath or a swim. Many have leather straps, which last longer kept dry anyway.

If you want a dress watch that doesn't need taking off for a shower, look for 5 bar or more, such as the CADISEN C8244, rated 10 bar.

5 bar (50 m): showers and a short swim

At 5 bar a watch can go in the shower and take a short swim at the surface. It isn't made for snorkelling, diving or long sessions in the water. Most of our 5 bar watches are digitals, such as the SKMEI 1251, SKMEI 2056 and NAVIFORCE 7104, and the SANDA 6287 is a women's 5 bar watch on silicone.

Don't press the buttons or pull the crown underwater, and avoid hot showers and saunas, which can weaken the seals.

10 bar (100 m): swimming and snorkelling

A 10 bar watch is the first we'd call a swimming watch. Swimming lengths, snorkelling and time at the beach are all fine. Look for a screw-down crown, which locks against the case and gives the seal more help. The ADDIESDIVE AD2065 GMT has one.

Our 10 bar watches are the CADISEN C8244, C8246 TI-7 and C7068, the ADDIESDIVE AD2065 and AD2095, and the Militado ML05 and ML22.

20 bar (200 m) and divers' watches

Diving needs a watch built for it. ISO 6425:2018 is the separate standard for divers' watches. It covers watches built for at least 100 m that have a way of timing a dive that can be read in the dark. According to Wikipedia's summary, every certified watch is tested individually rather than by sample, at 125% of its rated pressure, and passes extra tests including salt water and thermal shock. Certified watches are marked "DIVER'S" with the depth.

Our only dive watch is the BERNY AM339MS, a Miyota 8215 automatic rated 20 bar with an internal rotating bezel for timing dives. It suits swimming and recreational diving with both crowns screwed down. BERNY doesn't say the watch is ISO 6425 certified, so treat it as a well-specified dive-style watch and have its seals checked every couple of years if you dive with it.

Keeping a watch water resistant

  • Never pull the crown or press a button in the water.
  • Screw the crown down before swimming, on watches that have a screw-down crown.
  • Keep it out of hot water. Hot showers, baths and saunas can weaken the seals.
  • Have the seals tested. Wikipedia notes that most makers recommend a pressure test and new seals every one to three years if you swim with the watch. Any watch repairer can test one.
  • Have a battery change done properly. Opening the caseback disturbs the seal, so ask for the gasket to be checked when the battery is replaced.

Our 12-month warranty covers faults in normal use but not water damage from use beyond the watch's rating, which is why every product page lists the rating in its spec table.

Questions

Can I shower with a 5 ATM watch?

Yes. 5 ATM is the same as 5 bar, which covers a shower and a short swim. Avoid hot showers, and don't press the buttons while it's wet.

Is a 30 m water resistant watch waterproof?

No. 30 m (3 bar or 3 ATM) covers rain, splashes and washing your hands. Take it off before a shower, a bath or a swim.

Can I swim with a 10 bar watch?

Yes. A 10 bar (100 m) watch is fine for swimming lengths and snorkelling. If it has a screw-down crown, screw it down first.

Is ATM the same as bar?

For watch ratings, yes. 3 ATM, 3 bar and 30 m all describe the same rating.

Can I dive with a 20 bar watch?

Only if the watch is built for diving, with a dive bezel and screw-down crowns, and its seals are in good condition. Watches certified to ISO 6425 are marked "DIVER'S". A 20 bar rating on its own doesn't make a watch a dive watch.

Does water resistance wear off?

Yes. Seals age, so a watch that passed its test when new may not hold the same rating years later. A watch repairer can pressure-test it and replace the seals.

Sources

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