5 ATM, 10 ATM, EN13319: how to read a watch's water resistance
ATM (atmospheres) is a watch water-resistance rating based on static pressure: 5 ATM equals the pressure at 50 m depth in a lab, 10 ATM 100 m. EN13319 is a European standard for diving accessories, indicating that a watch is suitable for scuba diving.
In plain words
ATM figures are like a grade "on paper": in the lab the watch is submerged in still water under pressure. But in real life water moves: you dive in, jump into a pool, a wave hits the watch - and pressure spikes instantly. So "50 m" on a watch does not mean "you can dive to 50 m". It is like a seat belt: built to take an impact, but better not to test the limits.
How it works
- The watch is tested in a chamber under static water pressure.
- 1 ATM roughly equals the pressure of 10 metres of water.
- 5 ATM is for swimming in a pool and at the sea surface.
- 10 ATM is for swimming, snorkelling and water sports.
- EN13319 and ISO 6425 are diving standards with additional tests.
Where you'll see it
In the specs of smartwatches, bands and classic watches: "5 ATM", "10 ATM", "100 m", "EN13319". In our watch comparisons, the Protection row, often alongside IP68.
Does it matter when buying
Yes. For the pool and the sea, 5 ATM is enough. For surfing, water skiing and snorkelling, 10 ATM is better. For scuba diving, only watches with EN13319 or ISO 6425 and a dive mode. Do not press buttons underwater unless the manufacturer allows it, and avoid hot water and saunas.
Myths
- Myth: 5 ATM means you can dive to 50 metres. Reality: No, it is lab pressure; diving requires dive certifications.
- Myth: IP68 and 5 ATM are the same. Reality: IP68 is for accidental immersion; ATM is aimed at swimming.
FAQ
Can I shower with a 5 ATM watch?
Mostly yes, but soap, shampoo and hot water damage the seals.
Can I wear it in the sauna?
No, high temperatures damage the seals and the battery.
What is EN13319?
A European standard for diving equipment, including dive-computer watches.
Related terms
IP68 and IP69, MIL-STD-810H, Solar charging watch