A guide to water resistance

Some Casio watches are marked as ‘water resistant’, while others include an indication of depths, such as ’50 metres’, ‘100 metres’, or ‘200 metres’. These depths are based on static water pressure (in accordance with ISO 2281, International Organisation for Standardisation), as opposed to dynamic water pressure.

Static Water Pressure - What does it mean?

The term ‘static water pressure’ refers to the pressure of water at various depths when neither the water or the watch is moving. If you dive into a swimming pool while you are wearing a watch, the pressure on the watch is momentarily quite high as you hit the surface of the water. Equally, the pressure exerted on a watch were to you swim at a depth of 50 metres is far greater than stoic water pressure.

Water-Resistant (No Depth Indicated)

Watches marked ‘water resistant’ with no indication of depth will resist splashes and normal exposure to rain. They are not designed to resist water during bathing, showering, or activities that result in equivalent pressure. No buttons should be used while the watch is wet. The crown of an analogue watch should not be pulled out when the watch is wet.

50 Metre Water-Resistant

Watches marked ‘water resistant’ and ’50 metres’ will resist splashes and normal exposure to rain, as well as moisture during other activities such as swimming, bathing and immersed in water for washing up, car washing etc. Again no buttons should be used under water and the crown of an analogue watch should not be pulled out when the watch is wet.

100 Metre Water-Resistant

Watches marked ‘water resistant’ and ’100 metres’ will resist splashes and normal exposure to rain as well as moisture during other activities such as car washing, bathing, showering and swimming. They are also water resistant whist pool side diving and snorkelling, but NOT for high diving. Buttons can be operated underwater, with the expectation of those recessed into the case (adjust button). The crown of an analogue watch should not be pulled out when the watch is wet.

200 Metre Water-Resistant

Watches marked ‘water resistant’ and ’200 metres’ will resist splashes and normal exposure to rain, as well as moisture during other activities such as car washing, bathing, showering and swimming. They are also resistant whilst scuba diving to normal amateur depths ie. 35-40 metres; and suitable for high diving. Buttons can be operated underwater, with the expectation of those recessed into the case (adjust button). The crown of an analogue watch should not be pulled out when the watch is wet.

Water-Resistant Seals

In every case water resistant seals should be replaced by Casio or an authorised Casio agent at least every 2-3 years, regardless of the need to the battery of not.