DOXA’s Fine Form Continues With The New SUB 300 Carbon COSC

DOXA’s Fine Form Continues With The New SUB 300 Carbon COSC

Light, resistant, precise, and very cool to look at, DOXA’s latest release ticks all the boxes.

By Steven Rogers

For the past year, DOXA has been on something of a roll.

The historic Swiss brand has managed to take lockdowns, travel restrictions, and global uncertainty in its stride to come out with not one, not two, but three cracking novelties that have all hit the spot with watch aficionados.

Following the launch of the SUB 300 Carbon Aqua Lung US Diver limited edition and the resplendent, non-limited revamp of its iconic SUB 300, DOXA then added a chronograph to its SUB 200 line. 

Now, the Bienne-based watchmaker is following up that hat-trick of successes with what looks set to be another triumph: The SUB 300 carbon COSC.

It’s All in the Name

The name itself already indicates three cool things this watch has going for it. First, it’s a SUB 300, i.e., a dive watch icon and water-resistant to a depth of 300 meters (980 feet). Second, it features a forged carbon case that is light, resistant, and looks awesome. And, third, its automatic movement boasts coveted COSC-certified precision.

Moreover, a choice of stylish colors – six for the dial and five for the rubber strap – combine to create no fewer than ten SUB 300 carbon COSC references, all non-limited.

Each eye-catching version is versatile enough to offer dive-related high performance when wrapped around a wetsuit sleeve one day before coolly complementing a leather jacket and t-shirt around town the next.

On top of all that, the more-than-fair price point – $4,000 (CHF 3,790) – puts the SUB 300 carbon COSC firmly on track to be a winner.


The storied history of the SUB 300 line begins in 1967 when, having set out to create a diver's tool-watch that was accessible to all, DOXA launched the first SUB 300 model. It was revolutionary.

Its bright orange dial, covered by curved Plexiglas, made it far more readable in the murky ocean depths, especially compared to other dive watches of the time that tended to have black or white displays.

It was also the first diver to feature a unidirectional bezel with a dual dive time and depth indication, a feature that DOXA patented.

Skip forward to the modern-day, and DOXA has been making studied efforts in recent years to ensure that contemporary incarnations of the SUB 300 not only do justice to the original iconic diver but also build on its legacy.

And with the SUB 300 carbon COSC, DOXA has brought the SUB 300 well and truly into the 21st century.

Winning Ingredients of the Original

All the ingredients that made the 1967 edition so appealing are still present, starting with the super clear, highly readable indications.

On the dial itself, central hours, minutes, and seconds are complemented by a date window at 3 o’clock, with the generously-sized hands and hour indices boasting Super-LumiNova inserts to enhance readability in the low light of deep dives.

Covering the dial is a glass box scratch-resistant sapphire crystal that bears a dome shape evoking the original’s curved Plexiglas.

And framing all that is the famed, patented, unidirectional rotating bezel featuring the dual indication of dive time in minutes and depth in meters to calculate and monitor dive duration for a safe ascent without decompression stops.

Awesome-Looking Forged Carbon Case and Bezel

The first thing bringing this SUB 300 up to date – and projecting it into the future even – is that the case and bezel are made of forged carbon.

This modern material sees randomly worked carbon fibers mixed with resin and molded at high pressure and high temperature to produce a composite that performs really well and that looks amazing.

Indeed, forged carbon has got an excellent resistance-to-lightness ratio when compared to steel, for example.

So even though the case is not the daintiest – 42.5mm in diameter, 45mm lug to lug, and 13.4mm to the top of the crystal – the fully assembled watch weighs a mere 87 grams (3.06 ounces) once the rubber strap has been attached (more on that in a minute).

That lightness makes the SUB 300 carbon COSC really comfortable to wear. And not just on a diving expedition but also when casually out and about on dry land.

Bold, Edgy and Technical Looking

The aesthetic appeal of forged carbon can’t be understated either.

While there is a unifying, gentle sheen to the case and bezel, each fiber stands out, taking it in turns to reflect light as you turn the SUB 300 carbon COSC and creating alternating shades of charcoal and black.

The result is a watch that is bold, edgy, and technical-looking. It is a thoroughly contemporary aesthetic that is only enhanced by the different combinations of the dial and strap colors on offer.

Pick a Color, Any Color

When it comes to the dial and strap options for the SUB 300 carbon COSC, color is very much on the menu.

Six dial colors are available: “Aquamarine” turquoise, “Divingstar” yellow, “Caribbean” navy blue, “Searambler” gray, “Sharkhunter” black, and, of course, the “Professional” orange tone so emblematic of the SUB 300’s origins.

These dials can be paired with either a rubber strap in black or the same tone as the dial, except for the gray dial, where black is the sole strap option.

The strap is made of soft rubber, adding to the watch’s wearability, and features a black PVD-coated folding clasp that includes an extension function allowing it to fit over a wetsuit sleeve.

Vibrant, Personal Statement

While the black-on-black version caters to those looking for something a bit stealthier, the other funkier colors all provide an eye-catching contrast to the dark carbon case and allow the wearer to make a vibrant, personal statement.

My pick would be the navy “Caribbean” dial paired with a blue strap. It is understated and discreet yet with a flash of color provided by the orange minute hand and dive depth scale.

Previously, the only forged carbon dial offering from DOXA was the aforementioned SUB 300 Carbon Aqua Lung US Diver, a 300-piece limited edition featuring yellow and white accents.

The advent of the SUB 300 carbon COSC therefore gives DOXA fans the chance to have a forged carbon SUB 300 just the way they want it.

COSC-Certified Automatic Movement

Powering the SUB 300 carbon COSC is the ETA 2824-2 automatic movement with a 38-hour power reserve. With this workhorse of a self-winding caliber, you already know you’re getting robustness and reliability.

But DOXA raised its status here by having it certified as a chronometer by the independent testing institute COSC, ensuring its top-notch timekeeping accuracy.

The movement is housed in a pressure-resistant titanium chamber which, together with the screw-down crown and black PVD-treated titanium case back, optimally protect the caliber.

Price and Versatility Make a Winning Formula

The appeal of the SUB 300 carbon COSC lies in its versatility and value proposition.

On the one hand, it is the update of a highly legible, iconic dive watch, packing a chronometer-grade movement housed in a cutting-edge case, all for a reasonable $4,000.

Plus, the mechanical properties of the forged carbon – lightness and resistance – make the watch eminently wearable and add a high-tech dimension to the SUB 300’s story.

But on the other hand, it is the striking appearance of the carbon combined with the eye-catching dials and straps on offer that make the SUB 300 carbon COSC more than just a timepiece for the briny deep.

It performs just as well when worn as a bold, casual statement on the wrist during everyday adventures on dry land.

The SUB 300 carbon COSC is available now on DOXA’s website

(Photography by Pierre Vogel)

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