Waterproof Watches Holiday
The term “waterproof watch” is a misnomer — no watch is truly waterproof. What watches have is a water resistance rating, and understanding what those ratings actually mean in practice is the difference between a watch that survives your holiday intact and one that comes back with condensation fogging the dial. This guide explains the rating system and which watches from OD’s Jewellers are genuinely suited to active holiday use.
ATM Ratings: What the Numbers Mean
ATM stands for “atmosphere” — a unit of pressure. A watch rated to 3 ATM was tested to withstand pressure equivalent to three atmospheres, or approximately 30 metres of static water depth, in laboratory conditions. The critical word is static. Real-world use involves movement, temperature change, and impact — all of which create dynamic pressures that exceed the static test rating.
| Rating | Static Depth | Safe Activities | Avoid |
|---|---|---|---|
| 3 ATM / 30m | 30m | Splashes, light rain, hand washing | Showering, swimming, any submersion |
| 5 ATM / 50m | 50m | Brief contact, accidental immersion | Swimming laps, snorkelling, diving |
| 10 ATM / 100m | 100m | Swimming, snorkelling, surface water sports | Scuba diving, high-impact water sports |
| 20 ATM / 200m | 200m | Recreational diving, snorkelling, all swimming | Saturation diving |
| ISO 6425 Dive | 200m+ tested | Professional and recreational scuba diving | Saturation diving (requires specialist equipment) |
The Key Misunderstanding
- A 3 ATM watch is NOT suitable for showering — the dynamic pressure of water from a showerhead exceeds 3 ATM
- A 5 ATM watch is NOT designed for swimming — arm strokes create dynamic pressures above 5 ATM
- 10 ATM is the minimum rating most experts consider suitable for regular swimming
What “Water Resistant” Actually Means
When a watch is marked “water resistant” without any ATM number, it meets the minimum international standard: 3 ATM. This means it can survive rain and accidental splashes. It does not mean you can shower in it, swim in it, or submerge it deliberately.
Dynamic Pressure vs Static Testing
A watch is tested in a static pressure chamber at the factory. When you dive into a pool, the impact generates a pressure spike many times greater than the static depth you entered at. When you move your arm through water at speed, the pressure on the case increases beyond what you might expect at that depth. This is why a 10 ATM watch is rated for swimming but not for scuba diving — the dynamic pressure from kicking fins and rapid descents can exceed what a 10 ATM case is designed to handle.
Seals Degrade Over Time
Water resistance is not permanent. The rubber and synthetic gaskets that create seals around the caseback, crown, and crystal degrade over time through exposure to UV, temperature cycling, chlorine, and normal ageing. A watch that was rated to 10 ATM when new may offer significantly less protection after several years without a seal check. If you regularly use a watch in water, have the seals inspected every two to three years.
Important: Crown Position Matters
On a screw-down crown watch, the water resistance rating only applies when the crown is fully wound down and locked. If the crown is in the pulled-out position for time-setting and the watch enters water, the seal is broken regardless of the ATM rating.
Pool vs Sea vs Shower: Which Activities Require Which Rating
Showering
Counterintuitively, showers are harder on watches than calm pool swimming. The showerhead creates dynamic pressure, temperature fluctuates rapidly (thermal shock stresses seals), and soap and shampoo degrade gasket rubber over time. You need at least 5 ATM to shower comfortably, and 10 ATM is strongly recommended. With any watch, the safest habit is still to remove it before showering.
Swimming Pool
Calm lap swimming generates relatively low dynamic pressure, but chlorinated pool water is highly aggressive to gaskets and metal components. 10 ATM is the recommended minimum for regular pool swimming. After swimming, rinse the watch under fresh water to remove chlorine residue.
Sea and Open Water
Salt water is more corrosive than fresh water and adds the risk of wave impact. 10 ATM is the minimum for sea swimming and snorkelling. For anything involving depth — scuba diving, free diving — you need a watch rated to at least 20 ATM, and ideally one that meets ISO 6425 certification. Always rinse with fresh water after salt water exposure.
Safe at 5 ATM
Handwashing, light rain, accidental pool entry. Not recommended for deliberate swimming or showering.
Safe at 10 ATM
Recreational swimming in pools and sea, snorkelling, water sports on the surface. Not for scuba diving.
Safe at 20 ATM
All surface water activities plus recreational scuba diving. Citizen Promaster Diver is rated here.
ISO 6425 Certified
Independently tested professional dive standard. Additional requirements including legibility, anti-magnetic, and shock resistance.
Best Holiday Watches at OD’s Jewellers
Tissot Seastar 1000 — 300m / 30 ATM
The Tissot Seastar 1000 is a serious dive-capable watch rated to 300m (30 ATM), significantly beyond what most holiday activities demand. It features a unidirectional rotating bezel, screw-down crown, and solid caseback. The Seastar is built to ISO 6425 dive watch standards. On holiday, this is a watch you can genuinely wear in any water environment without anxiety. Available with bracelet or rubber strap options.
Browse our Tissot Watches collection to see current stock.
Citizen Promaster Diver — 200m / 20 ATM
The Citizen Promaster Diver is powered by Eco-Drive — no battery changes required, ever. It is rated to 200m (20 ATM), ISO 6425 certified, and built from Super Titanium™ — 40% lighter than stainless steel and significantly more scratch-resistant. The Eco-Drive system charges from any light source, making it perfect for a sunny holiday where you are outdoors frequently. After two weeks in the sun, it will have months of power reserve.
Browse our Citizen Watches collection for current stock.
BOSS Sport — 10 ATM / 100m
The BOSS Sport range is the brand’s most water-capable collection, rated to 10 ATM. This makes it suitable for recreational swimming and pool use. It is not a dive watch and should not be used for scuba diving. The Sport collection uses silicone or textile straps that handle water contact better than leather. If you want a stylish, on-trend watch that handles holiday swimming, the BOSS Sport is a strong choice.
Browse our BOSS Watches collection for current stock.
Quick Comparison
- Tissot Seastar 1000: 300m / ISO 6425 — serious dive capability, screw-down crown, bezel
- Citizen Promaster Diver: 200m / ISO 6425 — Eco-Drive, titanium, no battery
- BOSS Sport: 100m / 10 ATM — recreational swimming, stylish, non-dive
Maintenance After Water Exposure
Even a watch rated to 200m benefits from basic care after water exposure:
- Rinse with fresh water after salt water or pool exposure to remove chlorine and salt residue
- Dry thoroughly with a soft cloth, paying attention to the bracelet links, clasp, and around the crown
- Do not operate the crown or push-pieces while the watch is submerged unless the manufacturer explicitly states it is safe to do so
- Do not change the time immediately after water exposure — allow the watch to dry first
- Check seals periodically if you swim regularly with your watch — every two to three years is a sensible interval
Top Picks at OD's — In Stock Now
Three best-sellers our customers are choosing this month — all in stock, ready to ship from St Helens, available to try in our St Helens store before you buy.
All available in-store at 41 Barrow Street, St Helens, WA10 1RY — try before you buy.
Browse the full jewellery range at OD's.
Frequently Asked Questions
What does “water resistant to 50m” actually mean in real life?
A 50m (5 ATM) rating means the watch survived static pressure testing equivalent to 50 metres of water depth at the factory. In real use, it means the watch can handle handwashing and brief accidental immersion in still water. It is not rated for swimming or deliberate submersion, because dynamic pressures generated by movement in water exceed the 5 ATM static rating. For swimming, 10 ATM (100m) is the recommended minimum.
Can I wear my Tommy Hilfiger watch in the pool on holiday?
It depends on the specific model. Tommy Hilfiger watches vary in water resistance — some are rated to 3 ATM (splash only), some to 5 ATM, and some sport models reach 10 ATM. Check the caseback of your specific watch for the rating. If it says “water resistant 5 ATM” or less, remove it before swimming. Only Tommy Hilfiger models rated to 10 ATM or above are suitable for pool use. See our Tommy Hilfiger water resistance guide for detail by model.
Does chlorine damage watch seals?
Yes, over time. Chlorine is a chemical oxidiser that degrades rubber and synthetic gasket materials. A single pool session will not destroy seals, but regular, repeated exposure to chlorinated water without rinsing accelerates gasket deterioration. Rinse your watch with fresh water after every pool session and have seals inspected if you swim frequently with a watch on your wrist.
Is the Citizen Promaster suitable for scuba diving?
Yes — the Citizen Promaster Diver is rated to 200m (20 ATM) and holds ISO 6425 certification, which is the international standard for professional dive watches. ISO 6425 certification requires additional testing beyond ATM ratings, including anti-magnetic performance, luminosity standards, and shock resistance. It is a genuine tool watch built for diving environments. Browse our Citizen Watches range for current Promaster stock.
My watch is fogging inside the crystal — what happened?
Fogging inside the crystal means moisture has entered the case, which indicates a seal failure. This should be addressed by a watchmaker promptly — moisture inside a watch case causes corrosion to the movement. Do not continue wearing or exposing the watch to water. Bring it in to us at OD’s Jewellers and we can advise on next steps and refer to the appropriate service centre for your brand.