What Is A Dive Watch?

We’re going to look at what makes a dive watch, the features that make a diving watch different from any other watch and also take a very brief look at the history and evolution in an attempt to offer an evaluation about which is the best divers watch. Will the best be a prestige brand like Rolex or Breitling, or perhaps something a little more humble like a Citizen or Casio?

Whatever it turns out to be, even with the best will in the world ‘The Best Divers Watch’ will, of course, be a subjective issue because it depends on the individuals’ circumstances and requirements, not to mention budget.

So anyway, simply put, the dive or diver’s watch, is similar to any other wrist watch with the addition of some special features that have been developed over its surprisingly long history dating back to the 17th Century although it was not until the 19th Century that design and development sped up in response to the needs of an elite groups such explorers and professional divers.
For example in 1926 Rolex created the new ‘Oyster’ watch, featuring an advanced hermetically sealed case, which was successfully tested and publicized in 1927 by English swimmer Mercedes Gleitze’s attempting to cross the English Channel wearing the Oyster around her neck.

Mercedes Gleitze Rolex

Mercedes Gleitze Rolex

Further down the line Omega was to build the first industrially produced diving watch designed specifically for commercial distribution in 1932, naming it the Omega Marine.

Omega Marine

In 1935 the Italian Navy commissioned the design and production of a watch capable of operating at depth with the addition of luminous markings for use in poor visibility situations. The result of this came in the form of the ‘Radiomir’ made by Rolex introduced in 1936, closely followed a number of timepieces built to military specifications both during and after WWII by Hamilton, Elgin and Waltham, although only produced in relatively small numbers and not intended for large scale distribution.

Radiomir 1935

Radiomir 1935

Jump ahead to 1953 France and the Lip-Blancpain ‘Fifty Fathoms’ is introduced and issued in modest quantities to the allied military forces including US and French Navy combat diver teams, but probably most famously worn by Jacques Cousteau and his divers during the underwater film ‘Le monde du silence’. The following year Rolex re-entered the race with the introduction of the ‘Submariner’ debuting at Basel Fair as Reference 6204, which later went on to become the iconic timepiece of choice in the early James Bond movies.


As we can see, it’s been the military pushing the envelope of watch design and the manufacturers are responding by making newer and better offerings. By 1959 the United States Navy Experimental Diving Unit had been busy evaluating the top of the crop that included the Bulova US Navy Submersible Wrist Watch, Enicar Sherpa Diver 600, Enicar Seapearl 600, Blancpain Fifty Fathoms, and the Rolex Oyster Perpetual.

The push to develop better and better timepieces was in full swing and by 1961 Edox launched the Delfin line of watches, resistant to 200 meters, and by 1963 introduced the Hydrosub resistant to 500 meters.


Through the 60s, 70s, and 80s a lot of work was done and the water resistance attained just got better and better in response to the requirements of both military and civilian organizations working at greater and greater depths. The result of this increasing demand for better performance was the introduction of advanced watch design, a good example being the Rolex Sea-Dweller that is designed to operate at 2000ft or 610meters, and in 1996 ISO 6425 was introduced by the International Organization for Standardization (ISO), which set out standards and features for diving watches.
Dive Computer Watches

As a side note, many Divers now wear a dive computer or decompression meter as a more user-friendly alternative or backup to the very reliable diving watch.

Rolex Sea Dweller

Standards and Features of Diving Watch: In Brief
If you are looking for the quick run through of the features defined by the ISO here is a short list followed by a more in-depth description below.
1. A unidirectional bezel with at least at every 5 minutes elapsed minute markings and a pre-select marker to mark a specific minute marking.
2. A clearly distinguishable minute markings on the watch face.
3. Readability at 25 cm or 9.8 in total darkness.
4. An indicator to confirm the watch is running in total darkness. Normally a running second hand with a luminous tip.
5. Magnetic resistance.
6. Shock resistance.
7. Chemical resistance.
8. Strap/band solidity.
9. An End Of Life (EOL) indicator on battery powered watches.

Oddly, compliance here is voluntary and involves costs so not every manufacturer present their watches for certification according to this standard.
Watch cases must be water resistant and be able to endure the galvanic corrosiveness of seawater and provide protection against external magnetic influences and shocks. Case materials used are grade 316L or 904L austenitic stainless steel and other steel alloys.
Elapsed time controller

As you will have seen analog diving watches will often feature a rotating bezel normally featuring 15 to 20-minute markings. This allows for an easier reading of elapsed time of under one hour from a specific point. Divers use this to compute the length of a dive which they need to keep track of in order to avoid diving sickness on a non-decompression dive for example.

If you have never used this tool it may seem a little mysterious so let’s take a quick look at its operation. The Diver initially aligns the zero on the bezel with the minute hand to show the elapsed time to be read from the bezel, saving the Diver from having to remember the exact point of entry and carry out the appropriate calculations to understand the correct exit time.

As a safety feature the bezel will only be unidirectional to prevent a miss reading and giving a false reading if moved, and in addition, some Dive Watch have a locking bezel option to prevent any unwanted underwater operation.

Digital Dive Watches

Digital dive watches will normally perform the elapsed time function by utilizing the standard stopwatch function. But in addition, they may feature a depth gauge and logging features, making them a great tool for divers, however, as good as they are they are not considered a replacement for the dive computer.

Glass or Crystal

The glass or crystal covering the watch face is under considerable pressure while underwater so needs to be strong. The Crystal is built relatively thick to protect against this pressure and most likely has a dome shape to increased pressure resistance and like wearing a pair of glasses increasing the visibility at the same time in poor lighting conditions. There are three common materials used to make the crystal and they all have their plus and minus points. For example, Acrylic glass is resistant to breakage but scratched easily, Hardened Glass is scratch resistant but not so resistant to breakage, and Sapphire is very resistant to scratches but less resistant than the other example to breakage. The other option available to manufacturers is the combination of Sapphire and Hardened glass with a laminate, giving the best properties of both materials, with both scratch and shatter resistance combined.

The Crown

Dive watches sometimes house their crown in unusual places such as 4 o’clock or 9 o’clock to avoid discomfort. These crown are required to be water tight and some have the ability to be locked with a screwing thread, or even a locking arm or handle that needs to be moved to gain access to the crown.

Helium Release Valve

This is quite a special bit of kit for deep or extended dives. During deep or extended dives Helium builds up and is absorbed by the human body but equally this gas will build up in any space that has gas present such as the space between the face and the crystal. This is why some specialized watches has a Helium release valve to prevent to unequal pressure build up blown off the crystal

We could go into depth here if you pardon the pun, but in the simplest of terms the strap needs to be able to resist pressure and the corrosive nature of the environment and can be made from many different materials like rubber, fabric, titanium. Another thing that divers like in their watch strap is the ‘oversize’ allowing for the watch to be worn over the diving suit.


You need to see it!
This is really recapping on previous ideas but basically, the Dive Watch must be readable in low light conditions. All the dials and markers on the watch face and bezel must be legible underwater and in poor light conditions, with the important addition of a running indicator. This is to show the Diver the watch is still functioning and is usually conveyed by a luminous second hand. Moreover, all markings are uncluttered and luminous for low light operation using luminous phosphorescent non-toxic strontium aluminates.

Power Reserve Indicator

Another important feature of a diving watch is to understand when the power is running low. For a battery powered watch movement, an End Of Life (EOL) indicator is installed.
This is normally in the form of a two or four-second jump of the second hand or a warning message on a digital display to safeguard against insufficient power reserve during underwater activities. Some electric and mechanical powered movement models have power reserve indicators that show the current power status of the watch.

A Word About Water Resistance Classification.

You will have no doubt looked at the classification on a nice watch and maybe it says Water resistant 50m, and you thought quite reasonably this watch is good to go diving with up to the depth of 50 meters. Unfortunately, things are not quite that simple.

The guide below outline the true meanings of the water resistance measurements.
*Water Resistance Rating Suitability Remarks
*Water Resistant or 50 m Suitable for swimming, no snorkeling water related work, and fishing. NOT suitable for diving.
*Water Resistant 100 m Suitable for recreational surfing, swimming, snorkeling, sailing and water sports. NOT suitable for diving.
*Water Resistant 200 m Suitable for professional marine activity and serious surface water sports. Suitable for skin diving only. NOT suitable for scuba diving.
*Diver’s 100 m Minimum ISO standard (ISO 6425) for scuba diving at depths NOT suitable for saturation diving. Diver’s 100 m and 150 m watches are generally old(er) watches.
*Diver’s 200 m or 300 m Suitable for scuba diving at depths NOT suitable for saturation diving. Typical ratings for contemporary diver’s watches.
*Diver’s 300+ m for mixed-gas diving Suitable for saturation diving (helium enriched environment). Watches designed for mixed-gas diving will have the DIVER’S WATCH L M FOR MIXED-GAS DIVING additional marking to point this out.

You are probably asking ‘Why?’. Why say it’s water resistant to 50 meters when it’s only resistant to getting caught in the rain? Ok, so I exaggerate a little for effect but still, swimming pool or snorkeling is NOT 50 meters so why say that!??

Well, I am sorry but a don’t know why ‘there’ settled at this but I can tell you why a 30 meters watch no good for diving. It’s basically down to the specifications and the testing environment, you see when a watch is pressure tested the non-dive watch is tested once and only on a sample watch. So, it is never expected to withstand these pressure for long periods with an environment that is constantly changing. The diving watch, on the other hand, is repeatedly tested and at differing pressure and with safety margins to account for the aging of the watch parts.

Liquid Filled Watches

The final feature I want to mention is the liquid filled watch. As it suggests, the case is filled with liquid, but not any liquid, no this is silicone or fluorinated oil. This oil helps to equalize to the outside pressure and also help visibility by reducing refraction.
This technology works very well and has been proven to work at a depth of 12,000 meters or 39000ft which as you will agree is deep with a capital D. As good as this technology is, there exists a small drawback in that it only works on quartz movements, and a quartz movements will fail at 5,000 meters. Still, 5000 meters is nothing to sniff at right?

Sinn UX (EZM 2B) certified to 12,000 meters
Modern brands

This is no big deal, simply clean your watch in fresh water after a dive, have your dive watch pressure checked every year and replace seals and gaskets when required.
Basically, if you look after your dive watch, it will look after you.
So what’s the best dive watch then and how are we possibly going to choose among the hundreds of designs to come up with a winner?

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carl scutt
carl scutt
Carl's the founder and editor of discountwatchstores.com. His background's in Technology and Internet Marketing. He currently lives in southern Spain. Learn more about him here, and connect with him on Twitter, Facebook, Google+.

About carl scutt

Carl's the founder and editor of discountwatchstores.com. His background's in Technology and Internet Marketing. He currently lives in southern Spain. Learn more about him here, and connect with him on Twitter, Facebook, Google+.

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