Monochrome Watches
An online magazine dedicated to fine watches

Diving With the Omega Seamaster Diver 300M

Taking Omega’s classic dive watch where it belongs, under the waves…

| By Derek Haager | 11 min read |
Omega Seamaster Diver 300M Co-Axial Master Chronometer 42mm White Dial

Let’s play a word association game. When you hear the name “Omega,” what is the first thing that pops into your head? If you’re like me, it instantly conjures up thoughts of Speedmaster chronographs and space exploration. This is no small thanks to Omega’s marketing prowess and (well-deserved) pride at being on the wrists of the men who boldly went where no man had gone before. But it is at the other pinnacle of exploration where you will find the longest-running watch in Omega’s vast catalogue: the Seamaster. And for another of my diving trips, I took the most classic yet ultra-accomplished model underwater, the Omega Seamaster Diver 300M.

Omega Seamaster Diver 300M Co-Axial Master Chronometer 42mm White Dial

First released way back in 1948, the Seamaster was Omega’s answer to the growing demand for a tough, everyday wristwatch. Based on the success and watchmaking know-how they honed making over 110,000 timepieces for the British military during World War II, the first Seamaster was a robust, do-it-all timepiece, with even better water resistance than its military forebears, thanks to the innovation of the rubber o-ring gasket to keep the elements out. 

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While these watches were sturdy, waterproof and more aesthetically suited to civilian life than their military predecessors, it wasn’t until 9 years later, in 1957, that Omega released its first proper, civilian dive watch, complete with timing bezel and 200 metres of water resistance: the Seamaster 300. That watch gained its bona fides when it was used by Jacques Cousteau and his team on the CONSHELF II underwater habitat experiments in 1963. The rest, as they say, is history.

Omega Seamaster Diver 300M Co-Axial Master Chronometer 42mm White Dial

The Seamaster line has been in constant production, in many different varieties ever since. While it is probably most well-known to non-watch people as the timepiece worn by some bloke called James Bond, beginning with his portrayal by Pierce Brosnan and continuing until present, the Seamaster can be found in every configuration you can possibly think of; quartz or mechanical, men’s or women’s, square or circular, they have made them all. The current lineup consists of the Seamaster Aqua Terra, which is the modern version of that original, non-diving Seamaster; the Seamaster Planet Ocean collection, which is reserved for the chunkiest and most water-resistant dive watches of the line, the recently-launched Seamaster 300, a vintage re-edition of the iconic 1957 watch, and the watch we are looking at today, the Seamaster Diver 300M.

The Seamaster Diver 300M line was revamped in 2018, upgrading it to an in-house, Master Chronometer-certified movement, with this white colourway following a year later in 2019. A bit of a sleeper hit, it has slowly gained popularity, especially in the enthusiast community, over the past few years. We are going to put this classic Seamaster through its paces, with a day of sailing and a day of diving, and see if it lives up to its provenance as a watch for all activities, maritime and otherwise. But first, let’s look over the details.

Omega Seamaster Diver 300M Co-Axial Master Chronometer 42mm White Dial

The Omega Seamaster Diver 300M – The basics

At its core, the Seamaster Diver 300M is a 42mm stainless steel tool/dive watch. That alone puts it in league with some of the fiercest competition in the watch world, from some of the heaviest hitters out there. At 13.7mm thick and 50mm lug-to-lug and with a lug width of 20mm, it fits squarely in the “just right” sizing category, at least for me. The case finishing is a nice combination of polished and brushed surfaces, including the iconic Omega twisted lugs. The brilliant white polished ceramic dial features the etched wave pattern that has been emblematic of the Seamaster since 1994. Just under the centre of the dial, if you look very closely, you will see the engraved symbol “Zr02” which lets you know the dial is made of the ceramic material Zirconium Oxide. I don’t know if this is necessarily pertinent information to have displayed right on the dial, but it is subtle enough that you probably won’t even notice it unless you are looking for it. 

Omega Seamaster Diver 300M Co-Axial Master Chronometer 42mm White Dial

Elsewhere on the dial, you will find applied markers filled with a white Super-LumiNova and thin black borders for contrast. The Omega logo is just below the 12 o’clock markers where you would expect it, and below that is the iconic Seamaster logo in a bright, radiant red. This, along with the tip of the lollipop second hand, is the only colour on the dial and I found it to be the perfect amount. Something about the little bits of red amongst all the white and black make it pop in just the right way. I found myself just looking at it intermittently throughout the day, even when I had no desire to know what time it was. The polished, blackened hour and minute hands are skeletonized and filled (as much as skeleton hands can be) with the same Super-LumiNova, as is the lollipop part of the second hand. 

Omega Seamaster Diver 300M Co-Axial Master Chronometer 42mm White Dial

The bezel is a polished black ceramic with white indices and Arabic numerals every ten minutes. Things are sealed up with a screw-down crown at 3 o’clock, and there is a helium release valve at 10 o’clock. I’ll discuss that and the bezel in more detail down in the diving section, so read on. 

Around the back you will find a sapphire caseback, protecting the true star of the show here, the Omega Master Chronometer Calibre 8800. This is Omega’s METAS-certified automatic movement, featuring a co-axial escapement and free-sprung balance with silicon balance spring. This movement has a 55-hour power reserve and beats at the oddball cadence of 25,200 vibrations/hour (or 3.5Hz frequency). Omega says that is the optimal frequency and they surely know better than I do. The bidirectional rotor is finished with Geneva waves in arabesque. If you aren’t familiar with the METAS certification, it is a set of eight additional tests for movements that have already been COSC certified, so you are truly getting the “Master Chronometer” advertised on the dial. (Much) More on that topic in this video here. 

Omega Seamaster Diver 300M Co-Axial Master Chronometer 42mm White Dial

Above the Sea

I had the opportunity to take the Seamaster Diver 300M sailing and diving, thus trying it out in all conditions sea-related. The first day we took it out in the Gulf of Mexico for a day on the water. The white dial of the Seamaster gives it a head start here, in that it already looks substantially more nautical-themed than its blue and black counterparts within the collection. There are no real timing-intensive tasks involved in recreational sailing, so the wristwatch is only used for what 99% of people want them for anyway: telling time and looking cool. And the Seamaster is indeed a master of both of those things. 

It perfectly straddles the line between tough and toolish and elegant and classy. So whether you are close-hauled and hiking to windward, or enjoying a glass of wine back at the marina, the Seamaster Diver 300M looks the part perfectly. The size and dimensions feel just about perfect on my 16cm wrist. Big enough to know it is there when you need (or want) to look at it, but sleek enough that it doesn’t get caught up in any of the numerous halyards and sheets involved in sailing. And if you happen to accidentally fall in the water? The Seamaster has you covered there too, with water-resistance aplenty. As a sailing, boating, or just all around maritime watch, the Seamaster has everything you need in a tidy little package. Now let’s see how she fares UNDER the sea, but before…

The topic of the Helium Escape Valve

Before we go diving, let’s talk about the helium escape valve. As you may or may not know, that little one-way valve on the side of some dive watches serves only one, very specific function: allowing helium molecules to escape the watch during the decompression stage of a saturation dive. Considering that this is a task that 99.9999% of us humans will never undertake, having one of these valves is generally a useless, although cool feature, in an esoteric sort of way. I have a few watches with them and when I do randomly notice it is there, I’ll think “oh right, neat” for about five seconds and then forget all about it for another year. The HEVs that are recessed into the case, such as on the Rolex Sea-Dweller and various other dive watches are largely innocuous features. Not really useful, but not in the way either; you could take it or leave it. Having never worn a Seamaster Diver 300M before, I always found the active HEV at 10 o’clock to be an odd design choice. 

Omega Seamaster Diver 300M Co-Axial Master Chronometer 42mm White Dial

Why have it sticking out of the case when you could just recess it? Why make it active instead of passive? There is a decent chance, with the stress and checklists already involved in a five-day decompression, that I would forget to unscrew the little crown to activate it anyway. So I will admit to having gone into this review with a slight bias against the active HEV. Now, after having worn it for a week or so, I can happily report: it’s fine. It didn’t necessarily grow on me as a feature, but it didn’t bother me like I thought it would, either. Truth be told, after initially pondering it for a few minutes, I pretty much forgot it was there altogether. Just like a HEV should be. Now with that out of the way (and since it plays no role in recreational diving anyway), let’s get in the water.

Omega Seamaster Diver 300M Co-Axial Master Chronometer 42mm White Dial

Below the Sea

We all know that the days of timing our dives with just a watch are long past. Computers have taken over that role and many others to the great improvement of safety in modern diving. Being relegated to a backup timer leaves our mechanical timepieces with one other important job: a memory collector, of sorts. Outside of the watches, I am fortunate enough to review, I have a very select few personal watches that I take diving with me, and I always make sure to wear a certain one when doing anything extra-memorable, such as achieving a new depth or gaining a new certification, or any kind of milestone. That way, years down the road when I look back, I will know that this particular watch was with me through all of that, and perhaps those stories will be passed on to whoever gets it next. You get the picture. 

Omega Seamaster Diver 300M Co-Axial Master Chronometer 42mm White Dial

As that type of totem, the Omega Seamaster Diver 300M leaves very little to be desired; it could easily be a person’s one dive watch for life. The white dial and contrasting, lumed indices are highly visible and legible, even deep underwater. The rubber strap that this one came on is very comfortable and has plenty of length to fit over a wetsuit. It is hands down the most comfortable and high-quality OEM rubber strap I have ever worn. The watch continues its excellent wearability below the waves, being right there when you need it and blending away into your wrist when you don’t. 

Omega Seamaster Diver 300M Co-Axial Master Chronometer 42mm White Dial

My only small complaint with the watch when diving lies with the bezel. Where you will generally find a ridged, gear-tooth-esqe pattern around a bezel to facilitate maximum grip, the Seamaster has larger, curved recesses for traction. The result is a bezel that is a little harder to grip and rotate than I would like, especially with a neoprene gloved hand. It’s manageable and not a deal-breaker, but it could be a little bit better.

Omega Seamaster Diver 300M Co-Axial Master Chronometer 42mm White Dial

Final Thoughts

All things considered, I think the Seamaster Diver 300M completely lives up to its name. It is a one-stop watch for all things maritime, and it does it with class and style. As a 42mm, sub $10k steel dive watch, Omega is in a very crowded field, amongst some of the heaviest hitters in the game, most notable the Rolex Submariner and Tudor’s Pelagos and Black Bay lines. I am pleased to say that it holds its own in that weight class and then some. I think there is a tendency to think of the Seamaster as a runner-up, the watch you settle for when you can’t get another one, due to certain scarcity issues out there in the world. You would be doing yourself a great disservice to think this way. This watch has the build quality to match any of the other big boys out there, if not surpass them, and a certain indefinable charm that is all its own. 

Now available for USD 5100 or EUR 5,000 from Omega boutiques, retailers and online at

11 responses

  1. This is a watch I have had some interest for some time, in fact, I own an Omega GMT divers watch with a co-axial movement and along with a ridiculous helium release valve which has the appearance of an acne pimple which is a poor afterthought of design.
    My Omega GMT CO-AXIAL dive watch has had costly problems; when the hour hand reaches 11:00 the hour hand ceases to go further unless I disengage the hour hand and move it manually to 12:00 then it works perfect until the hour hand once more arrives at 11:00.
    As for the helium escape valve, I have never used it. Why is this?
    All my life I have remained at ground level.
    So why did I purchase the Omega GMT divers watch?
    Second Answer:
    It’s Robust, has a screw down Crown and is a beautiful time piece…..with serious flaws. Plus I believed the Omega hype.
    Omega needs to make their Seamaster 300 without the helium escape vale protruding as though it a design afterthought and with at 39 or 40mm along with a guarantee the Seamaster 300 hour hand will proceed past the eleven marker without having to manually move the hour hand past the eleven hour marker. If Omega did this, they would double or triple the sales of the Omega Seamaster 300 watch.

  2. Another great Omega article from Monochrome Watches but with one issue – stop using the Seamaster Diver 300 for its intended purpose you are making the rest of us look bad! As for the issues with the a Seamaster that cannot move its hand beyond 11 O’clock this is absolutely nothing to do with the helium escape valve. The valve aperture does not have any direct contact with the movement of the watch especially the gearing for the hour hand. There is nothing that protrudes into the case from the helium escape valve. The watch needs a full service as it sounds as though the gearing is catching on a foreign body or has worn down due to a lack of lubrication. If necessary Omega will replace the movement under warranty if the watch is still under warranty. Every time the watch is serviced by Omega it is given a two year warranty. It therefore pays to get your watch serviced regularly to keep up the warranty. I have owned 5 Omega watches with helium escape valves and have never had any issues with them and none have ever had the problem described. No Omega watch with a helium escape valve has this issue either. It is unique to the commentators watch. I am amazed the watch has not been repaired yet.

  3. Nice, but I don’t think that it compares well with the Pelagos.

  4. The only downside is the association with a fictional character in the movies. Otherwise, Omega has resolved any problems earlier versions of this watch had through some good development. Highly desirable.No games.

  5. I would choose this stylish, uncomplicated everyday, everywhere watch over the Unobtanium fake conceit any day.

  6. What a great written article ! Almost felt like I was brought along on that boat/diving trip, and just came a little closer to wanting an SMP . Thanks !

  7. The Omega Seamaster 300M with the white dial is awesome. I would love one with a titanium case.

  8. Omega sea with the white dial is lovely I’ll be adding one to my collection very soon, at the moment I’m loving my Seiko sbbn015 🔥

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