What Are Water Resistance Ratings for Diving Watches?

August 23, 2022 5 min read

When buying a diving watch, you'll want to look for the "water-resistant" rating. The 50-meter mark means that the watch is water-resistant for at least that deep. That doesn't necessarily mean it can be used for actual diving, though. This rating simply means that the watch is able to withstand the pressure of being underwater. The pressure inside of a watch varies significantly when it is under water. The pressure may cause a watch's seals to fail, or water may enter. Most water-resistant watches are not intended for active use in water for prolonged periods of time. Read if you can dive with a 100m watch.

20 ATM

A diving watch that has a 20 ATM water resistance rating is ideal for scuba diving. This rating is the safest level for recreational, shallow diving, and is often the minimum requirement for scuba diving equipment. While a watch can withstand a lower rating of 10 ATM, it is still important to make sure that it is durable enough to endure the pressure of the water. This article will discuss how to tell if your diving watch meets the minimum requirements.

A diving watch with a 20 ATM water resistance rating is suitable for most types of underwater activities. Its water resistance rating is determined by the pressure that is applied to the watch during swimming. A dive will result in a sudden change in pressure, and the watch must be able to cope with that sudden pressure change. The pressure of the water can also change rapidly, and a watch that has 20 ATM water resistance is not suitable for saturation diving.

30 ATM

A diving watch's water resistance rating is determined by its ability to withstand overpressure in water. This is typically measured using a 10-minute immersion in water and a force of five Newtons applied perpendicular to the crown and push buttons. A watch with a 30 ATM water resistance rating can handle this pressure for many hours. However, the operative parts of a diving watch must be water-tight to survive this test.

Although most watches are splash-proof, there are some exceptions to this rule. While most of them can survive an accidental splash or a shower, you should never wear a diving watch under water. The seal can wear down after a while and can be compromised when exposed to high-impact water activities such as scuba diving. In addition, a diving watch that is not water-resistant can break due to the pressure of a dive.

40 ATM

If you plan to go deep into the water, your dive watch should have a water resistance rating of at least 40 ATM. This rating is based on the pressure it will withstand under 125% of its rated pressure for one minute. The watch will also be tested against condensation and thermal shock. It will be submerged at 40 degrees Celsius for a minimum of 30 minutes. Then it will be subjected to five N of force at the buttons and crown. If this amount of pressure is not too much, then it is suitable for diving.

The 40 ATM rating is not a hard and fast rule. It is a guideline based on the experience of the watchmaker, and is largely unsuitable for professional sports. A watch's water resistance varies greatly with the temperature and other mechanical stresses it endures, and a diving watch's 40 ATM rating is only a guideline and should never be relied on for scuba diving.

50 ATM

Diving watches with a 50 ATM water resistance rating are designed to withstand extreme water pressure. These watches must be able to withstand 10 cm of water and a pressure of five Newtons for an hour. Additionally, these watches must resist hot temperatures and other mechanical stresses. For this reason, an ISO 2281 water resistance rating is important. This rating is often required by diving clubs. To see if your watch meets this standard, read on.

Some watches are better suited for water activities than others. However, before you wear a watch while underwater, make sure it has a 50 ATM water resistance rating. If it does not, it may crack because the water will leak into the watch's body. Some watches have a 50 ATM water resistance rating, but this rating is not sufficient for diving. Therefore, it is important to make sure that the watch you choose has this feature.

100 ATM

A 100 ATM water resistance rating for a diving watch means it can survive even under extreme conditions. Ideally, a diving watch should be able to withstand pressure at least 100 atmospheres, or 1 atmosphere per square meter. This pressure is caused by the diver's movements and is referred to as dynamic pressure. In other words, if a diver can swim at a speed of 50 meters per minute for one second, they should be able to survive at a pressure of 0.5 ATM.

The test is done in a controlled environment, which is similar to the actual pressure that a diver would experience underwater. In the case of a diving watch, a test is performed to simulate the process of decompression. To perform the test, the watch owner must remove the winding stem, the setting stem, and the crown. Next, a hole in the crown is made in the watch's case, and a gas mixture is introduced through it. After 10 hours of the test, the watch must function properly without the leakage of water or condensation.


The 6,000-meter water resistance rating on a diving watch is usually reserved for watches that are used in the deepest waters. However, there are some exceptions to the rule. The Titanium Divers watch, for instance, may be worn on land. Its titanium case may be more suitable for everyday use. The Titanium Divers watch is a bit larger than most other diving watches, but it still has a very impressive water resistance rating. Read our article about the deepest dive watch.

Extreme depth ratings aren't necessarily necessary for diving. Standard diving watches are rated at a maximum of 500-600 metres. 1,000-metre-water-resistant watches might be a little far-fetched, but they can provide great peace of mind for divers. There are many ways to measure how deep a dive watch can survive. There are two main tests for water resistance: ISO 2281 and mixed-gas diving. For mixed-gas diving, the watch is subjected to 125% of its rated pressure for 15 days. The overpressure must be reduced within 3 minutes. If the watch is still unable to withstand the pressure, it can be subjected to an optional ISO 2281 test, which consists of two bar overpressure with air entry allowed at 50 ug/min.

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