What Makes a Good Dive Watch? Water Resistance, Helium Valves, and 7 Key Features to Consider

A dive watch has a fairly straightforward job: keep working and keep telling you what you need to know when you take it underwater. Doing that well, however, demands more than just a high water-resistance figure.

Essentially, what makes a good dive watch are seven key features: dependable water resistance, a unidirectional bezel, a secure crown and case back, strong legibility, durable materials, a suitable strap or bracelet and, for certain professional divers, a helium escape valve.

Alongside these features, 200 metres of water resistance in a dive watch offers plenty of capability for most recreational scuba diving. The question, then, is how each element earns its place when the watch goes below the surface.

 

 

What makes a good dive watch? A quick checklist

 

 

1. Dive watch water resistance

Water resistance is usually the first figure people look at when choosing a dive watch. It’s also one of the easiest to misread.

A watch marked “200m” hasn’t simply been lowered 200 metres beneath the sea. The figure tells you how much pressure its case has been designed and tested to withstand under controlled conditions. It shouldn’t be treated as a recommended diving depth.

As a practical guide:

 

 

 

You may also come across ISO 6425 when looking into dive watch standards. Put simply, it helps distinguish watches genuinely designed for diving from watches that happen to be water resistant. Among its requirements, a diver’s watch must be designed for at least 100 metres and provide a secure, readable way of measuring time underwater. In other words, “100m” on the dial doesn’t make a watch a fully fledged diver.

So, can you swim with a 100m water resistant watch? Generally, a correctly maintained watch designed for that use can be suitable for swimming. For scuba diving, a dedicated dive watch with 200 metres or more offers greater capability.

At the other end of the scale, a 500m water resistant watch makes more sense when the watch is engineered for harsher professional environments. The Supermarine Full Ceramic Deep Blue sits firmly in that territory, with 500 metres of water resistance backed by a titanium inner case and helium escape valve.

And finally, does water resistance decrease over time? Yes, it can. Gaskets age, seals wear, and crowns see repeated use, so water resistance needs maintaining rather than assuming the figure on the dial is permanent.

2. Why do dive watches have rotating bezels?

The rotating bezel is one of the most recognisable diver watch features, but it’s there for a practical reason. Before entering the water, the diver lines the bezel’s zero marker up with the minute hand. As the hand advances, the bezel provides an immediate reading of elapsed time.

A proper dive bezel is normally unidirectional, meaning it rotates in one direction only. If it is knocked accidentally, it can make the dive appear longer, but never shorter. Crucially, it can’t suggest you have more time remaining than you really do. It’s simple, mechanical, and deliberately safe and cautious, which is what you want underwater.

3. Screw-down crown and case back

The crown is one of the obvious places where water could enter a watch. A screw-down crown threads securely into the case, while the case back, crystal, and internal gaskets complete the seal around the movement.

Before entering the water, the crown needs to be fully secured. It sounds simple, because it is. Even the best dive watch water resistance still depends on the case being properly sealed.

4. Why do dive watches have helium valves?

This is where things become more specialised. A dive watch helium escape valve is primarily designed for saturation divers, who can spend extended periods in pressurised environments using breathing mixtures containing helium.

Tiny helium particles can gradually make their way inside the watch case. During decompression, pressure outside the watch may fall faster than the gas trapped inside can escape. In extreme cases, that difference in pressure can damage or dislodge the crystal.

The valve gives that helium a controlled route out. That’s also why it serves a completely different purpose from a screw-down crown: the crown helps keep water out, while the helium valve lets trapped gas escape when required.

Do most recreational divers need one? No. On the Supermarine Full Ceramic Deep Blue, however, it sits naturally alongside 500-metre water resistance and a specification engineered for more demanding environments.

5. Legibility and lume

A dive watch isn’t much use if you have to study it to work out the time. Natural light fades as you descend, while water conditions can reduce visibility even further. Clear hands, strong contrast, and effective lume therefore matter a great deal.

The Supermarine Full Ceramic Deep Blue uses applied indexes and hands filled with Super-LumiNova® with blue emission, helping the dial remain readable in low-light conditions. It’s a design detail with a very practical reason for being there, ensuring full visibility while you take things further below the surface.

6. Case material and crystal

A serious tool watch needs materials chosen for more than appearance, and there isn’t one ideal case material for every dive watch. After all, different watch materials have different benefits and serve different purposes.

Stainless steel is a durable all-rounder, titanium offers considerable strength at a lower weight, and ceramic stands out for its exceptional scratch resistance and light feel. Sapphire crystal is similarly hard-wearing, making it well suited to a watch expected to see proper use.

The Supermarine Full Ceramic Deep Blue combines a ceramic outer case with titanium construction around the movement and a sapphire crystal, bringing low weight, durability, and scratch resistance together where each matters.

7. Strap or bracelet and fit

A dive watch needs to stay secure and comfortable on the wrist, particularly when conditions become less forgiving. Rubber is a natural choice around water because it is flexible and durable, while a NATO-style strap provides another secure option.

The Supermarine Full Ceramic Deep Blue can be paired with a Black Rubber Chevron Strap, a Black and Blue Woven Fabric NATO Strap, or a Blue Embossed Rubber & Leather Strap, giving you three distinct options depending on how and where you intend to wear the watch.

Whichever you choose, the key is a fit that feels secure without becoming cumbersome, whether the watch is worn directly on the wrist or over diving equipment.

 

How to choose the best dive watch for you

The best dive watch depends on how you plan to use it.

For recreational diving, prioritise dependable water resistance, a clear unidirectional bezel, strong legibility, and a secure fit. These are the features that prove their worth once you’re underwater.

For an everyday tool watch that needs to move easily between the water and daily wear, comfort comes further into the equation. Case size, weight, and material all matter, with lighter constructions such as titanium or ceramic helping the watch feel less cumbersome on the wrist throughout the day.

Professional requirements are different again. Key components including greater water resistance and more specialised features, such as a helium escape valve, begin to make sense when the environment genuinely calls for them.

The Supermarine Full Ceramic Deep Blue shows how those priorities can come together at the more capable end of the spectrum. It combines 500-metre water resistance with a unidirectional bezel, screw-down crown, helium escape valve, strong low-light visibility, and ceramic and titanium construction.

 

Why pressure testing still matters

A capable dive watch isn’t maintenance-free. Before it leaves the factory, its water resistance is checked under controlled pressure to confirm that the case, crown, crystal, and seals are all doing their job.

Those seals can deteriorate with age and use, even if there’s no obvious external damage. During servicing, pressure testing is used again to check that the case is still properly sealed and able to withstand the level of pressure it was designed for.

That matters because water resistance can change over time. At Bremont, we recommend having water-resistant seals checked annually, particularly if the watch is regularly exposed to water. With a dive watch, the important specification isn’t simply what it could withstand the moment it left the factory. It’s what it can withstand today.

Learn more about the testing that Aldo Kane put the Bremont Supermarine Full Ceramic Deep Blue through across Iceland’s glaciers and icy waters.

Take it further with the Bremont Supermarine collection

Ultimately, what makes a great dive watch isn’t one headline specification. It’s how the engineering comes together and functions against the conditions it’s designed for.

Water resistance, legibility, timing, materials, and fit all have a role to play. The strongest dive watches bring those elements together with purpose, creating something that feels considered, capable, and dependable when you actually take it underwater.

Explore Bremont’s Supermarine dive watch range today, crafted for the depths and engineered to help you take it further.

What makes a good dive watch FAQs

What features should a good dive watch have?

Look for suitable water resistance, a unidirectional bezel, strong legibility, a secure crown and case, durable materials, and a strap or bracelet designed for water use.

How water resistant should a dive watch be?

For most recreational scuba diving, a purpose-built dive watch rated to around 200 metres offers plenty of capability.

Is 300m water resistance enough for diving?

Yes. A correctly maintained 300m dive watch offers more than enough water resistance for typical recreational scuba diving.

Do I need a 500m water resistant watch?

Probably not for recreational diving alone. However, a 500m rating is relevant and useful for particularly demanding or professional underwater use.

Is a water resistant watch the same as a dive watch?

No. Water resistance is only one requirement. A proper dive watch also needs features such as strong legibility and a secure way to measure elapsed time.

Can I swim with a 100m water resistant watch?

Generally, yes, if the watch is designed for water use and properly maintained. Always follow the manufacturer’s guidance.

Why do dive watches have helium escape valves, and do I need one?

Helium escape valves allow helium trapped inside a watch during saturation diving to escape during decompression. Recreational divers generally don’t need one.

How often should a dive watch be pressure tested?

Follow the manufacturer’s guidance. Bremont recommends having the seals of its water-resistant watches checked annually.

Is a ceramic case good for a dive watch?

Yes. Ceramic offers excellent scratch resistance and low weight, making it well suited to dive-watch construction when engineered appropriately.

Which Bremont dive watches are water resistant to 500 metres?

The Supermarine Full Ceramic collection is rated to 500 metres and includes a helium escape valve for more demanding diving environments.