How to Choose a Waterproof Watch for Swimming? | 5 ATM vs 10 ATM Ratings

Before you shop, understand one thing: the industry’s “waterproof” label has been replaced by a water-resistance rating system, and the number on the case tells you what the watch survived in a lab, not how deep you can dive with it. The question of how to choose a waterproof watch for swimming actually comes down to matching that rating to where you’ll swim. Pick the wrong rating and your watch becomes a paperweight; pick the right one and it’ll handle years of laps.

The Water-Resistance Scale Explained

Water resistance ratings are measured in meters, ATM (atmospheres), and IP codes, and they don’t mean what most people assume. A rating of 50 meters (5 ATM) does not mean the watch is safe at 50 meters deep — it means the watch passed a lab test simulating water pressure at that depth while it sat still.

Here’s the honest breakdown of what each rating actually supports:

• IPX7 (splash/rain) — survives light rain and hand-washing, but Apple explicitly states submerging a watch with only IPX7 is not recommended. Not for swimming.
• 50 meters / 5 ATM / WR50 — the swimming baseline. Shallow-water activities like pool laps and ocean swimming are fine. Avoid scuba diving, waterskiing, or high-velocity water impact.
• 100 meters / 10 ATM / WR100 — open-water swimming, stronger water pressure, and more safety margin. Still not for scuba diving unless the manufacturer says otherwise.
• Dive-certified (200m+ with ISO 6425) — the only class meant for actual scuba use; these watches carry a dedicated dive certification, not just a depth rating.

The one table worth remembering:

The Apple Watch Example: What Official Ratings Mean in Practice

Apple’s own lineup shows exactly how manufacturers apply these standards. The Apple Watch Series 1 and first-generation models carry an IPX7 rating under IEC 60529, and Apple’s official support documentation says submerging these models is not recommended — they are splash-resistant at best. The Apple Watch Series 2 and later jumped to a 50-meter rating under ISO 22810:2010, which Apple says makes them suitable for shallow-water swimming in a pool or ocean.

The Apple Watch Ultra goes further: 100 meters under ISO 22810:2010 plus EN13319 compliance, which is a European standard for diving accessories. Apple says the Ultra can be worn for recreational scuba diving up to 130 feet (40 meters) — a distinction no standard Series watch gets. That progression is the entire water-resistance story in one product line: check the exact standard, read what the manufacturer says the watch is rated TO DO, and never assume the depth number is a diving permit.

Three things to verify before you buy, straight from the official spec sheet:

• The exact rating standard — ISO 22810, IEC 60529, or EN13319 mean different things; look for the specific standard on the product page.
• The word “water resistant” — if the manufacturer won’t even print “water resistant,” the watch is not for swimming. Apple uses “water resistant,” never “waterproof.”
• A swim mode or water lock feature — this locks the touchscreen and ejects water from the speaker after a swim; it’s the feature that makes a swim watch actually usable, not just safe.

Common Misconceptions That Kill Watches

The most expensive mistake buyers make is reading 50 meters as a depth limit. It’s not — it’s a lab-derived pressure rating that assumes the watch is stationary.

Equally common: taking a splash-rated watch swimming because it survived a rainy run. And scuba diving with a swim-rated watch, even a 100-meter one, is a gamble — only watches with a dive-specific certification, like the EN13319-compliant Apple Watch Ultra, carry a manufacturer warranty for that use.

Choosing the Right Rating for Your Swim

The decision narrows to your primary use. Lap swimmers and casual beach swimmers can confidently buy a 5 ATM / 50-meter watch — it’s built for exactly that. Open-water swimmers, snorkelers, and anyone who wants margin for rougher conditions should step up to 10 ATM / 100 meters. Divers go straight for a dive-certified model and skip the gray zones entirely.

One more reality check: water resistance fades with damage, wear, and environmental exposure — a dropped watch or a worn gasket leaks even at its original rating. Check the manufacturer’s current documentation before your first swim of the season, not just on day one. If you’re also choosing a watch for beach days, our tested roundup of the Best Beach Watches covers models that handle sand, salt, and surf — a different kind of abuse than laps in a chlorinated pool. Apple’s water resistance support page is worth reading before any watch purchase, as it explains the same standards in plain language.