The 5 year review
Doxa SUB 300 Carbon Aqua Lung US Divers Limited Edition
The Background
It’s crazy to think that it’s been more than five years since I purchased my Doxa SUB 300 Carbon Aqua Lung US Divers limited edition(yes that’s a very long name). A watch that I at the time was not expecting, but subconsciously always hoped for. A lightweight, well proportioned tool watch with great heritage, COSC ETA movement and plenty of water resistance. I bought it at the pre release and payed the rather substantial amount of €4790 (price now is €5090). A lot of comments at the time was that it was priced too high for an ETA powered Doxa. But I never quite agreed with this and I still don’t. Maybe because I didn’t consider at the resale value, but rather saw a watch that I had an actual use for.
I received the watch in august 2020 and a few days into owning the watch I found out that the minute hand was incorrect. Not exactly what you expect when paying almost €5000 for a watch. The lume which is supposed to be at the tip of the hand, was in the middle. It didn’t bother me but I contacted Doxa just to hear what they had to say. Apparently some of the watches had accidentally been fitted with prototype hands. They offered to replace it free of charge, but as I didn’t mind it, I thanked them and declined the offer. It’s now a fun detail that makes the watch a little different.
The Experience
Doxa knocked it out of the park with the feel and finish of this watch. I’ve owned a few over the years, including a vintage 300T shark hunter. All of them have had a quality look and feel about them, but the 300 carbon feels even better. It’s like a premium version of the sub 300. Everything from case finish to bezel action is super sharp and crisp, which makes handling the watch a treat. If I compare it to something like a Tudor Pelagos 42, I would say the build quality of the 300 carbon is possibly even more impressive. The two different materials could be one of the reasons, but it’s just something about the precision of all the edges and details on the 300 carbon, that makes it hard to not be impressed.
The specs say it’s 13mm thick, but the slim mid case, which is slimmer than the normal sub 300, makes it look and feel more like 10mm. Due to sharp lines I was honestly not sure how the carbon case would age. Even though I have quite a lot of experience with carbon in other gear, this was my first time with the material in a watch. Well, it turns out that it ages beautifully. After five years of hard use, I can only really notice tiny marks on the teeth of the bezel with a macro lens. On wrist it looks pretty much as it did when I first got it. The matte texture of the bezel has become slightly polished/glossy, but at a glance I think that’s the most telling sign that it’s not brand new.
To put things into perspective, It’s worth mentioning that the 300 Carbon has easily been my most worn watch these last five years. It’s been on my wrist in mud, sand, snow, lakes, salty sea water, mountains, hundreds of miles of running and cycling, ice bathing and much more. From this I have not just found that carbon is durable, but it’s also an excellent case material from a temperature standpoint. Carbon and titanium(case back) have lower thermal conductivity than stainless steel, which for me is actually quite a big deal, especially in the winter. The watch itself doesn’t really feel cold, which makes for a warm and happy wrist.
How well the Sub 300 carbon keeps on aging, I guess we’ll just have to wait and see. But judging by how well it’s handled these first five years, I’m highly confident in its durability.
The three negatives
This watch is quite niche and certainly not for everyone. I know for example that the low weight, which I love, has put some people off. It’s a great watch but over the years I have only found three things that I’ve considered negative. One of these is an easy fix, the other two I’ve just had to live with.
The first thing is the movement. This is a chronometer-certified ETA 2824-2. A good, service friendly and reliable movement which unfortunately has one weakness, the power reserve. In 2020 the 38h power reserve was acceptable, but now in 2025 I would have wished for more. Although, this is really only an issue If I were to buy it now, not so much five years ago.
Second negative is the strap. The Sub 300 Carbon comes with Doxas excellent rubber and a black PVD stainless steel clasp. It wears very comfortable, but the rubber and clasp combo weigh 48g(cut). That’s 3g more than the case including springbars! This means the watch ends up weighing 93g on the rubber(still less than a Fenix 8). However, because of this, the weight is pretty evenly distributed around the wrist, which is one of the reasons why it wears so well. But this is a carbon watch and for me it’s all about practicality and weight. Therefore I have almost exclusively worn the watch on different passthrough straps. My current and favourite is an elastic MN style strap in black with black hardware. A combo that weighs only 57g and hugs the wrist perfectly.
Third we have the lume. Now, this one is both good and bad. I have small children and usually sleep with my watch on, to tell the time when they wake up at night. So I want lume that makes it easy to tell at a glance. With this watch I get long lasting but very weak lume. It’s possible to tell the time in complete darkness, even after hours sleep, but you need to really focus. Which is not ideal. I think this is the case of not using enough Super-LumiNova on the markings. My Doxa 600T Pacific uses the same lume and shines like a torch.
Conclusion
After five years, the Sub 300 Carbon has proven itself to be a fantastic watch, and for me, a fantastic activity watch. The carbon case, even though its light weight, has handled my active and sometimes unforgiving lifestyle, showing only small signs of wear. The combination of carbon and titanium is not only light but also remarkably comfortable in all weather conditions, from hot summers to freezing winters. If I’m going up a mountain, a run or bike ride, this is what I reach for.
It’s genuinely one of the most practical and enjoyable mechanical watches I’ve owned. It’s not for everyone, but if you’re looking for a mechanical watch to replace your activity watch. This sure is a great contender, albeit not inexpensive. But you get what you pay for. A watch that’s special and cool enough to wear daily and light enough to wear on the side of a mountain or a long run. This is not like other Doxas, this both looks and feels like a step up.
