care · 2 min read
Is the Casio F-91W waterproof? Water resistance and everyday care
What 'water resist' means on a Casio F-91W, what it can and cannot handle, and simple care tips to keep the resin case and strap looking new.
By the F91W team ·
The short answer: the Casio F-91W is water resistant, not waterproof. The “WATER WR RESIST” print on the face means it handles everyday splashes, rain and washing your hands. It is not designed for swimming, showering or diving.
What “water resist” means on an F-91W
Casio marks the F-91W as water resistant for everyday use. In practice:
| Situation | OK? |
|---|---|
| Rain, splashes, hand-washing | Yes |
| Sweat during workouts | Yes, rinse it later |
| Showering | Best avoided (hot water and soap stress the seals) |
| Swimming or diving | No |
| Pressing buttons underwater | No |
Even when a watch handles some water, pressing its buttons underwater can let water past the seals. Keep the buttons dry.
If your F-91W gets wet
- Rinse off salt or chlorinated water with fresh water.
- Dry it with a soft cloth, paying attention to the gaps around the buttons.
- If you see fog inside the display, moisture has got in. Take it to a watch shop promptly so the module does not corrode.
Caring for the resin case and strap
Resin is light and comfortable but appreciates a little care:
- Clean it regularly. Wipe the case and strap with a damp cloth. Use a soft toothbrush for the strap grooves.
- Avoid harsh chemicals. Solvents, perfume and strong cleaners can dull or discolour resin.
- Keep it out of direct sun when you are not wearing it. Long hours on a sunny dashboard can fade bright colours, especially WC colourways like Sky Blue or Hot Pink.
- Dry the strap after sweat. Salt left on resin over time makes it stiffer.
Gasket and battery changes
The seal that keeps water out sits under the caseback. If you change the battery yourself, make sure the gasket goes back clean and evenly seated. Our battery guide covers what to watch for.
The bottom line
Wear your F-91W every day without worrying about rain or washing up. Just take it off before you swim. Treat the resin gently and it will look good for years.
Feature details from Casio F91W-1 specifications.
