30 m, 50 m, 100 m and 200 m are not activity instructions
A generic overview pairs 30 m with 3 atm, 50 m with 5 atm, 100 m with 10 atm and 200 m with 20 atm. That overview is a secondary source, so the activity advice below comes from the manufacturers’ manuals instead. Casio’s manual uses BAR markings without assigning metre figures. 6 6 6 6
Look on the dial or caseback for the exact words: WATER RESIST, 5 BAR, 10 BAR or DIVER’S 200 m. A bare “WATER RESIST” can describe everyday splash protection without a numeric rating. In Seiko’s table, that everyday marking does not permit swimming, while its 5 BAR marking does. 4 4
What the manuals permit
These are examples for the exact markings and manuals named in each row. “Skin diving” means diving without an air cylinder; “scuba” here means using an air tank. A Yes applies to that example, not every watch with a similar number.
| Marking and manual | Rain and splashes | Swimming | Skin diving | Scuba with a tank |
|---|---|---|---|---|
| Citizen WATER RESIST, 3 atm | Yes 1 | No | No | No |
| Citizen W.R. 5 bar | Yes 1 | Yes | No | No |
| Casio 5BAR | Yes 2 | Yes | No | No |
| Casio 10BAR | Yes 2 | Yes | Yes | No |
| Casio 20BAR | Yes 2 | Yes | Yes | No |
| Citizen (AIR) DIVER'S 200 m | Yes 3 | Yes | Yes | Yes |
Seiko’s 10 (20) BAR manual permits diving without an air cylinder; Citizen’s combined 10/20 bar chart permits skin diving and marine sports. Neither is a blanket permission for scuba diving. 4 1
What about a shower, bath or sauna?
Do not take a general “50 m = shower” chart as an instruction for your watch. The generic overview does list showering and bathing at 50 m, but the specific Casio, Citizen and Seiko documents checked here warn against baths or heat. Casio also warns about soaps and detergents; Seiko warns about running tap water on the case. 6 2 1 4
Why 200 m and DIVER’S 200 m are different
Casio’s daily-use 20BAR table permits skin diving, while its general precautions rule out diving with air tanks. The specific Citizen (AIR) DIVER’S 200 m instruction and Seiko 200 m diver instruction permit scuba diving. The Citizen air-diver instruction still rules out helium saturation diving. 2 2 3 5
Before and after contact with water
- Check the dial or caseback marking and the manual for your exact model.
- Keep the crown and buttons alone while the watch is wet or submerged, unless that model’s instructions explicitly allow operation. Casio’s checked manual forbids it, and Citizen’s chart marks wet operation No even for its air-diver example. 2 3
What this guide does and does not cover
The comparison is drawn from the water-resistance rows for Casio, Citizen and Seiko. The metre-to-pressure overview is secondary, and those figures do not replace an exact model manual. We do not yet have verified water-use tables for Timex, Orient or Bulova, nor do we have pressure-test results for individual used watches. See the source methodology or send a correction when a maker’s instruction differs from what appears here.