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August 05 2019

Although much of the Rolex name has been built on their relationship with the world’s ocean’s and those who explore them, water remains one of the biggest enemies of mechanical watches.

Since their invention of the Oyster case in 1926, a milestone that did more than anything else to bring wristwatches into the modern era, Rolex timepieces have withstood the elements better than most. However, even horology’s most successful manufacturer has its limits, and the underwater environment is an incredibly testing proving ground.

Waterproof or Water Resistant?


If you read up enough about watches, you will see the terms ‘waterproof’ and ‘water resistant’ used interchangeably—but they are, in fact, very different. The easy way to think about it is, there is no such thing as a 100% waterproof watch, not even from Rolex.

Waterproof suggests something that will stop water encroaching under any circumstances. While Rolex’s Oyster case watches, everything from the Datejust to the Deepsea, are among the best in the industry, forced to undergo some of the severest testing, they are still formed from a number of parts that have to fit together. Anywhere those components meet; the sapphire crystal over the dial, the case back, and especially the crown, is a potential weak spot where water can intrude if care isn’t taken.

It is for that reason the term ‘waterproof’ was outlawed by the FTC in the 1960s and replaced with the more accurate ‘water resistant’ when it came to watches.

Rolex Water Resistance

The water resistance of Rolex models really falls into three categories.


At the lowest end is the brand’s range of pure dress watches, the Cellini collection. Even though they are the only examples in the catalog without Oyster cases, they are still given a water resistance rating of 50m, helped along by their tapered, fluted crown which screws into the case. That means, technically, they can withstand the pressure of water pushing down on them at a depth of 50m.


Any Scuba enthusiast knows that is a long way down, below the depths most recreational divers will venture without advanced training. Does it mean, then, you can wear a Cellini on your next dive trip? No, it does not!

That 50m rating is given under static laboratory conditions, the watch slowly introduced to the increased pressure and doesn’t take into account the huge dynamic changes caused by movement underwater. The closest you should take a 50m-rated watch to a dive is when you’re rinsing off afterwards, and still then I probably wouldn’t risk it with a model costing well into five figures. Even snorkeling, where you would rarely descend below 10m, is out.


The next tier of water resistance in the Rolex portfolio are the non-dive Oyster pieces.

Rolex Oyster Perpetual Ref. 77080

These, thanks to the case design which has barely altered from that 1920s original, ensure a resistance of 100m—and here’s where it gets a little more interesting.

ISO 6425, the International Organization for Standardization rating, states that a 100m water resistance is the minimum for dive watches. So, again, could you time your next underwater excursion with a Daytona or a Sky-Dweller? And again, no!

A true dive watch has to withstand a whole extra battery of tests before it can be called so. And while 100m is a formidable depth for any human to dive to (the maximum for a PADI Open Water Diver is a mere 18m) it is once more a case of the extra pressure added on by moving about underwater. Even on the surface, say if you were jet skiing, a 100m grade isn’t enough to fully safeguard your watch against the force of the water hitting it at great speed. Jumping into and swimming in a pool, even a bit of snorkeling, are all fine with a 100m watch. Scuba diving? No.

Dive Watches

Rolex Sea-Dweller 4000 ft

The last level at Rolex is, of course, the trio of dive watches. Here we have models that are rated to at least 300m. That’s for the legendary Submariner. The bigger brother, the Sea-Dweller, is safe down to 1220m. And should you want to go looking for something around two-and-a-half miles underwater, the behemoth that is the Deepsea will reportedly keep working at an utterly incredible 3,900m.

These, you will not be surprised to hear, are ok to use far beyond the bath tub and down to any depth anyone will realistically ever go.

What Affects Water Resistance?

My car, according to the manufacturers, will give a fuel economy of 50.4mpg. However, due to a combination of factors, i.e. its age, my driving style (which has been described as both ‘delinquent’ and ‘volatile’) and the fact I haven’t bothered to have it serviced since 2013, means that figure is now not even close to reality.

It is not all my own fault though. The carmaker will have tested its economy in the most favorable conditions they could in order to get that figure, all the better to entice me in.

Rolex Submariner Aftermarket Ref. 16610

A lot of those points are transferable when talking about watches and their water resistance. Yes, a brand new Day-Date, one that literally just rolled off the line with all its seals intact, had never been knocked and was then assessed under the precisely controlled environments of Rolex’s lab, will most certainly win its 100m certificate.

But in the real world, there are a host of things that can degrade that performance over time. A water resistant watch doesn’t just stay water resistant out of the goodness of its heart.

Firstly, age will reduce the effectiveness of gaskets and seals, and they don’t have to deteriorate by much to start allowing moisture inside. Subjecting your watch to extreme temperature variations; for example, wearing it in a sauna or hot tub, will have a similar effect—even a hot shower will take its toll eventually, and comes with the other issue of the increased pressure forcing water in.

Any significant blow can misalign one of the rubber seals, and it will likely be something you won’t know about until it’s too late.

Also, using a third-party component can cause problems. For example, fitting a non-Rolex diamond bezel; the minute tolerances needed to ensure a perfect fit are something only the brand itself can be reasonably expected to accomplish.

And perhaps the most common one, forgetting to screw the crown back in after winding or setting the watch. It is something we have all done at one point or another. Sometimes you notice it in time and get away with it, sometimes you learn an expensive lesson.

What To Do

We all know prevention is better (and in this case, cheaper) than the cure.

If you wear your watch in the sea, whether diving or just splashing around, it is vital you wash it with fresh water afterwards. Salt water is extremely corrosive and will eat away at the metal and/or rubber seals over time.

In addition, make sure you stick to Rolex’s recommended servicing schedule—perhaps the most straightforward way of ensuring your watch retains its optimum performance.


The good news is, every model made since 2015 gets a suggested 10-year gap between maintenance appointments. It is important to remember however, that applies to what the brand calls ‘real-life usage’. If your Rolex leads a par

ticularly hard life, it will be in your best interest to up the frequency at which it gets a professional onceover.

Each one also gets a warranty when sold brand new, including its water resistance, of five years from the date the timepiece was purchased brand new from the authorized Rolex dealer; one of the longest of any luxury manufacturer. The myth that Rolex guarantees its watch’s will remain impervious to water for life has been doing the rounds for a long time and is, I’m afraid, just plain wrong.

So what is the best way to protect the integrity of your Rolex? Well, committing to having your watch pressure checked at least once a year is something that will save you a lot of money in the long run.

Most service centers will have the facility to do this, and the price for the test and to replace any seals or gaskets that may have failed is not an expensive day out. And certainly not in comparison to the fees that can pile up if water does actually infiltrate the case of your beloved piece.

If the worst happens and moisture does get in, time is very much of the essence. Getting your watch to a service center as quickly as you can will make the difference between being charged for just a service and a few extra parts, and receiving an eye-watering bill for, at best, a replacement dial and at worst, a whole new movement. In the case of the latter, it can sometimes work out cheaper to buy a new watch entirely.


When all is said and done, Rolex watches are incredibly well made and extremely resilient. Water getting inside is far more often a result of a mistake by the owner than anything else.

The important things are to respect the limits built into your particular model by not pushing the watch beyond what it was designed to do, sticking to an annual pressure check and, more than anything, making sure you screw that crown back in!