Watches and Water Resistance: Why would I need a 100m or 200m water resistant watch?

I’ve been thinking a lot about water resistance in Dive Watches. Specifically: what’s the point? 50 meters of water resistance makes sense to me. But the recreational limit for scuba diving is 40 meters. So 200m water resistance is kind of… pointless? To go down that deep, it would be a six hour technical dive on rebreathers and crazy gas mixes and super fancy equipment, and I doubt anyone would want to wear an expensive watch in that context. I guess this idea of “what’s the point” could be applied to just about anything in the watch world (Quartz vs. mechanical, etc) and the answer is all about the art of watch craftsmanship or somesuch, but for some reason, seeing a fancy watch company advertising a 200m water resistant watch on the back of one of my scuba magazines just bugged me. – Michael R.

As someone who has never even snorkeled, once ruptured his planter fascia jumping off a pontoon boat (yes really) and up until recently (like yesterday) thoroughly believed one of the major myths about watch water resistance (we’ll get to that) I am wholly unqualified to explain this.


The Seiko Samurai

The Seiko Samurai: Omega Planet Ocean Looks for $320

The Seemingly Contradictory Reality

Watch water resistance is really confusing. Along with all of the technical jargon and two separate sets of testing rules and methods (hot plates! carefully placed droplets of water! pressurized testing containers!) there also appears to be a ton of mostly de-bunked myths floating about. Here are two conflicting realities surrounding watch water resistance:

  • Wristwatch manufacturers will specifically tell you DON’T swim with a watch that has 30m water resistance or less.
  • You have people who ACTUALLY SCUBA DIVE using 50m Timex Ironman athletic watches as backups to their dive computers, and many divers will tell you that 200m or 300m is wayyyyy overkill.

30m but can’t swim with it? 50m is good for SCUBA diving and 200m is overkill? The hell is going on here? Which do you want me to believe?

The Orient Ray II. Automatic. Inexpensive. Plenty water resistant.

The Myth that Sounds Way Too Good.

One of the more believable myths about watch water resistance (the one I used to believe wholeheartedly) says that these two seemingly contradictory realities can actually co-exist because watches are usually tested statically. Meaning: They aren’t moving. They’re cooked up in a pressurized casserole dish or whatever, but the watch is just sitting there. And if you’re an average landlubber knuckle head who goes for the occasional dip, you’ll need that extra protection because swimming/smashing your hands into the water will greatly increase the stress put on the watch (Force = Mass x Acceleration). Doing a cannonball off the pier or swimming your way through waves really does a number on the crown, case, and gaskets, amiright?

The problem is, it’s just not true. It SOUNDS great, but, the truth is you can thrash all you want. You’re not gonna hurt your watch with your feeble human forces.

Nodus Avalon

The Nodus Avalon. A tremendously cool looking backup to the digital dive computer.

So if that myth (and all the others) aren’t true, why do watch manufacturers insist that a watch with 30m of water resistance isn’t good enough to play a quick game of Marco Polo with? It’s because, and this is speculation: They don’t trust their work. And perhaps most importantly, they don’t trust their customers. You and me included. Here’s what I mean:

It’s the crown, Stupid.

I’m stupid. You might be stupid too. The moron who was working the stump grinder for our tree removal job the other day and shredded right through a plainly visible sprinkler head and didn’t even realize it? Utter and complete broth-brain. Sometimes our gray matter just goes off the boil.

And if you’re stupid and forget to push the crown back in on your watch, then the water resistance is almost certainly zero. It’s not sealed. You have a leak. There is, in fact, a hole in your bucket dear Liza. More than a few times in my life I’ve had a watch on my wrist for an extended period of time and then, out of nowhere, I have noticed that the crown wasn’t “in.” How does this happen? I don’t know! I’m stupid! But if that’s the case when you hit the water, the water rushes in, and, blammo. Your watch is a paperweight. Also, pulling that crown out and pushing it in hundreds of times over the life of a cheap watch will almost certainly wear down those pieces parts, and make it more susceptible to failure/not securing correctly when you have pushed it in. And thus, watchmakers say: “Yeah, don’t swim with the 30m stuff. Safer for everyone.”

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Christopher Ward’s C65 Trident. 150m water resistant. No screw down crown.

Why I Still (foolishly) Rationalize 200m for Swimming

I personally don’t wear anything in the water with a resistance of less than 200m, because that makes me the most comfortable and those are usually the watches with screw down crowns. No screw down crown = a (small) risk of forgetting to seal the watch by securing the crown. It is one extra step to prevent me from being stupid. If I’m winding a watch or setting the time or date, I need to screw the crown in to be “done” with that process. That’s how I view it. THAT SAID I’ve done plenty of swimming and dancing in the rain with 100m rated watches and I haven’t had any trouble at all. Yet.

More Questions. More Rationalizing.

So why have an over-engineered dive watch that’s 100m, 200m or 300m water resistant? Let’s explore that. Why have a car that can go 160 mph? Why have a pair of fancy heritage work boots when you sit at a desk all day? Why would you want a vacuum cleaner strong enough to pick up a bowling ball? Or an amplifier that goes to 11? Because a lot of it is marketing. Or status. Or both. But, and perhaps this is a stretch, many products that are over engineered for tasks you’ll never perform seem to also feel, work, and let’s be honest, look better in day to day operation compared to the cheaper, less capable competition.

Casio MDV106-1AV

TL;DR: Water resistance marks are confusing, mostly antiquated standards which have been weaponized by brands for marketing. They also can (but not always) indicate overall fit, finish, and perhaps durability of a watch due to the phenomenon of over-engineered consumer products possessing associative, more easy to notice, quality and style advantages over cheaper competitors. Also, I concede that the above post is nowhere near thorough enough for any watch snobs reading this. I pray to Poseidon for your forgiveness.

STILL TL;DR: A Toyota Camry can go 130 mph. It is a fine automobile. James Bond drives an Aston Martin. ¯_(ツ)_/¯

Scuba Dive Watches:

A Buyers Guide To Water Resistance,
Bezels, Crowns And More

Scuba dive watches are one of the few pieces of scuba diving equipment that is useful both in and out of the water. You see all types of dive watches around.

And some people actually use them to go diving!

Many people wear dive watches as a fashion statement and other people add them to their watch collections.

It’s all good, but if you are diving with this watch you have to know what you are buying since you are depending upon it to keep track of your dive.

Here’s a guide to help you shop for dive watches and hopefully make the task a little easier.

(For much more information on watches take a look at our Dive Watch Buyer’s Guide including our picks for best dive watches at various price points.) 

Scuba Dive Watches: A Primer

The importance of a dive watch varies, depending on if it is your primary or secondary source of timing.

If this is your primary source of timing your dive, you need to get a high quality, dependable watch.

If you have a dive computer and the watch is serving as your secondary timing device, it is not as critical if the watch fails underwater. Of course, you don’t want this to happen but it won’t endanger you if it does.

It’s OK if you splash it in the pool, but that’s about it. The type of scuba dive watches you are looking for will be rated in either depth (feet or meters) or pressure.

As a recreational diver, even though you will not be going below 130 feet you should get a watch that is rated to at least 200 meters (660 feet) to be safe.

This is the recommendation by most guidelines. The reasoning behind this is that the watch is tested under controlled circumstances. That is, the watch and the water are both static. If there is any movement, be it the watch or the water, the pressure on the watch increases.

Having a higher rating allows for movement of the diver and any bumps, jarring, etc. that may occur. Scuba diving watches rated for 200 meters should be dependable under all normal diving circumstances.

If this is your primary timing device, try getting one with the higher water resistance rating. Seiko provides the following chart to determine what type of water resistance you need.

  • Water-resistant: OK for accidental splashes; should not be worn while swimming or diving.
  • Water-resistant to 50 meters: Suitable for normal swimming.
  • Water-resistant to 100 meters: Suitable for swimming,snorkeling and other water sports (except scuba diving).
  • Water-resistant to 200 meters: Suitable for all of the above and for scuba diving if it complies with international standards for divers watches (Seiko’s watches are marked divers watch).

A scuba diving watch with bezel.

Most good dive watches come with this type of bezel, but check to make sure.

The unidirectional bezel will only turn in a counterclockwise direction. This means that if you knock the bezel and it moves, it can only move in the conservative direction (opposite the way the minute hand is moving).

Thus the watch will show that you have been down for a longer period of time, rather than a shorter period of time (which would happen if the bezel moved in the other direction) if the bezel is accidentally moved.

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The bezel should also be tight enough that it needs some effort to move it around the dial. You’ll feel it go against the internal indents as you move it.

Test it out and make sure it is easy to hold. There are usually indentations on the outer edge of the bezel to give you a firm grasp and make it easier to move.

If you are unfamiliar with a bezel, it is a metal ring that goes around the face of the watch and has point indicators on it.

The bezel also has a zero mark to designate the starting point. To use the bezel, you turn it until the zero mark lines up with the minute hands.

Scuba Dive Watches: Other Considerations

Other things to consider when you shop for dive watches are:

  • Clear Face – A clear face is the best option for scuba dive watches. You want to be able to see the information clearly and quickly.
  • Screw Down Crown and Backs – A good dive watch should have a screw down crown rather than the push/pull crown that most dress (non-water) watches have. This gives the watch a better watertight seal. Backs that screw down rather than just press in also provide a tighter seal.
  • Luminous Dials – Luminous dials make the watch face easier to read in low vis situations and/or night dives.

These are some of the basics to consider when you shop for dive watches.

For more information, check out our other pages on watches:

Here’s to a perfectly timed dive!

Want to stay down longer and improve your buoyancy control and other diving skills? Our free report “Increase Your Bottom Time” along with our practical, weekly actionable tips will have you looking like a seasoned diver in no time. So come join us and see improvement on your very next dive!
(Click on the photo to join us now!)

Watch Water Resistance: A Definitive Guide to the Rating

Water resistance is one of the most important factors to consider when purchasing a watch, especially if you plan on using it for activities such as swimming, snorkeling, or diving.

Therefore, it is essential to know what water resistance on a timepiece means.

However, what makes it complicated is that the resistance rating isn’t always exactly what it says – there are a lot of misconceptions and ambiguity to this simple number.

In this article, we will explain everything you need to know about the watch water resistance rating. So, whether you are shopping for your first timepiece or just want to learn more about this feature, read on!

Watch water resistance

Water Resistance on Watches

The watch’s water resistance rating indicates how much pressure the watch can withstand before water seeps in. It’s usually measured in ATM (atmospheres) or meters of depth, but other units are used as well, such as feet and bar.

The water resistance rating is usually marked on the caseback of watches but sometimes features on the dial as well.

So, what does an ATM rating mean?

One atmosphere (1 ATM) is equivalent to the air pressure at sea level. So, a watch with a water resistance rating of 10 ATM can withstand air pressure of up to 10 atmospheres, or 100 meters (about 330 feet) underwater.

Most watches have a water resistance rating of between 30m (3 ATM) and 300m (30 ATM), but there are some that go up to 1,000m (100 ATM).

21,800 vph Seiko automatic professional dive watch

But how to know if a watch is simply water-resistant or waterproof? Because besides professional divers also exist dive-inspired watches that look like professional ones but are not suitable for deep diving.

The truth is that differentiating between a waterproof and a water-resistant timepiece isn’t easy visually because the writings don’t often tell much or are ambiguous.

Therefore, it is best to check the watch description provided by the reseller or visit the watch manufacturer’s page for more information.

However, some watches can be instantly identified as waterproof – they have the writing “Diver’s,” followed by the number. Such timepieces with the Diver’s marking are ISO 6425 watches for professional diving.

But what exactly is ISO 6425?

ISO 6425 & Dive Watches

ISO 6425 is an international standard for dive watches that was introduced in 1996 by the International Organization for Standardization (ISO). This standard specifies requirements for watches intended to be used underwater.

The most important one is that it must be at least 100 meters water-resistant, which means that it must be able to withstand pressures up to 10 ATM (100m) without failing. The truth is that the vast majority of dive watches sport at least a 200m rating, with only a few 100m ISO divers available.

Other requirements include the existence of a time indicator (unidirectional bezel), luminosity, corrosion test, and resistance tests against physical, magnetic, and thermal shocks.

In other words, ISO 6425 dive watches are professional-grade timepieces that can be submerged to specified depths.

Seiko dive watch with Pepsi bezel and Hardlex and ISO 6425 certification

However, the ISO 6425 standard is not compulsory for watch companies to determine dive watches. Instead, many have opted against going for the recognition but conduct their own tests.

Several luxury brands, including Rolex and Omega, carry through similar tests, if not even more rigid ones. Also, several affordable Swiss brands don’t carry the ISO recognition but instead state of being in compliance with their own testing.

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Therefore, ISO 6425 has several alternatives of how to determine the so-called waterproof watches.

Various Water Resistance Ratings Explained

Now we know that if a watch is “waterproof,” it will withstand the stated water pressure.

But what about water-resistant watches that aren’t waterproof? To what extent can, for example, a 30m water-resistant watch be in contact with water? Or what about the 200m watch?

Although water-resistant watches are not waterproof to indicated depths, they still can be waterproof to some extent, depending on their resistance levels and the activities they are used for.

30m (3 ATM) Water-Resistant

3 ATM, or 30 meters (100ft), is the lowest water resistance contemporary watches feature. The rating guarantees protection against splashes of water and light rain. It means the watch withstands only mild contact and should be kept away from the water as much as possible.

50m (5 ATM) Water-Resistant

50m of water resistance guarantees you a carefree watch wearing in the rain and during hand washing. Also, the chances of ruining the watch during swimming are pretty low. However, it still isn’t advisable to use a 50m water-resistant watch for frequent swim sessions.

100m (10 ATM) Water-Resistant

Now, this is the rating that allows you to wear your watch for swimming, snorkeling, and other surface water sports. The timepiece withstands long sessions in the water, as long as you don’t submerge it deeper than 1m (3ft).

200m (20 ATM) Water-Resistant

200m water-resistant watch is spot-on for swimming and snorkeling, but also for recreational diving to depths up to 40m (130ft). However, there are still no guarantees that the watch will withstand the pressure 40 meters deep because it very much depends on the watch and the manufacturer producing it.

For example, wearing the Orient Kamasu with a 20 ATM resistance 40 meters below the water surface is much safer than wearing a 200m water-resistant timepiece from a fashion brand.

Therefore, a 20 ATM watch can be used for diving, but it is best to go for a professional-grade diver instead when you wish to wear it for this activity without worrying about ruining the watch.

300m (30 ATM) Water-Resistant

If the watch features a 30 ATM water resistance, it means it is spot-on for serious water sports, including swimming, snorkeling, and recreational diving, despite missing the ISO 6425 certification.

Watch Water Resistance Chart

To make the complicated water resistance ratings and their suggested ways of use easier to understand, have a look at the following chart.

watch water resistance chart

Healthy Tips

1) Don’t wear your watch when showering – unless you like to take cold showers without using any shampoos or shower gels, it is not a good idea to take your watch with you.

The thing is that watches and hot water don’t go well together because when the water cools down, the moist air absorbs into the watch case. When done constantly, the movement starts to degrade.

Another factor affecting the well-being of your watch is the use of shampoos and gels while showering. Since they consist of chemicals, they have a negative effect on the rubber gaskets and glues that secure the watch’s water resistance.

2) Don’t operate the crown (and pushers) underwater – the watch crown and pushers are the most vulnerable parts of watches where the water can intrude into the case. If they are operated underwater, you can be sure the watch is ruined for good.

Also, make sure the crown is pushed in (or screwed down) if dipping into the water.

3) The leather strap is not for water – out of all the types of watch straps, leather is the least suitable for water activities because of its porous characteristic. When it gets wet, it absorbs the moist into the pores and eventually deteriorates the structure.

In Conclusion

So, what to make of the watch’s water resistance rating?

First off, the resistance stated on the caseback and dial is not the depth you can submerge the watch because it is not tested in real-life conditions. The actual limitations are far more stringent when a 30m water-resistant watch withstands only splashes of water, and a 100m water-resistant watch should be used for swimming at the most.

Secondly, you have to differentiate between a water-resistant and a waterproof watch – the latter can actually withstand the pressure at the stated depth underwater. These watches are called dive watches that employ either ISO 6425 standard or have been tested by the watch manufacturers themselves.

Therefore, you should consider the extent you are going to use your watch in terms of water contact.

For example, if your lifestyle consists of long office hours or staying indoors, you should be okay with a 3 ATM or a 5 ATM timepiece. However, if you like to swim or exercise in other surface water sports, go for a 10 ATM or a 20 ATM watch. And finally, if you wish to take on scuba diving lessons in the near future, then a 30 ATM timepiece or ISO-certified dive watch is your best fit.




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