Using the same (or a very similar) case design as that of the Military, the Poseidon is offered only in brushed steel and measures 42mm wide, 14.3mm thick, and 45.3mm lug-to-lug. Fitted to the included light grey Isofrane rubber strap, the Poseidon weighs in at 127g and boasts 300 meters of water resistance, a steel case back, a sapphire crystal and bezel insert, and a blocky Military-esque dial with a date at three.

Those paying attention may have caught the minor detail that splits the limited production run in half. It’s the hour hand and the seconds hand. In an edition of 1,000 Poseidons (Poseidie?), Synchron is making 500 with those hands in white, and 500 in black. A subtle difference to be sure, but if you’re very picky about your hour hand coloring, I suppose it’s always nice to have options. Those with a very keen eye will also note that the Poseidon logo on the black version is ever so slightly larger than on the white one, chalk that up to prototyping as the white-handed version in these images is an earlier design and the black-handed version represents the retail product.  

Otherwise, the exterior design language reflects the Synchron Military and its homage to the Doxa Army of the 1970s. The most considerable change here is with the plongeur hands and the coloring, with the Poseidon having a light grey center dial, yellow accents, and bearing the (deeply cool) Poseidon logo – which we have seen on more than a handful of past Doxa models.

I don’t want to belabor the specific history of Poseidon (the dive equipment company), but some context could be helpful. The brand was founded in 1958 (then under the name Aquasport) and it was the first scuba manufacturer to design and offer a single hose regulator, a design that has since become the standard for conventional diving. The brand continued to innovate in diving and would later release the first-ever recreational rebreather. Today, they are a leading brand in the diving space and produce an array of diving equipment that is used all over the world, including by the diving elements of the Swedish Armed Forces.

Poseidon had a pre-existing relationship with Synchron’s current leadership and the result of the exercise is this limited edition. The military connection is also the impetus behind the Poseidon not sporting the same ETA movement as the preceding Military. 

According to Sycnhron, the watch needed a power reserve that offered a longer duration than the ~40 hours of an ETA 2824 (or similar). As such, the Synchron Poseidon employs a La Joux-Perret G100, which is an automatic Swiss-made movement meant to operate as a higher-spec option for watches designed around the 2824 platform. With 68 hours of power reserve, this 4 Hz movement is adjusted in four positions.

The Poseidon is being released in conjunction with Cold Divex 2023, a military demonstration held by the Swedish Armed Forces in Boden, Sweden. According to Synchron, the diving units of the Swedish Armed Forces will be testing specialized versions of the Poseidon in this arctic environment. 

On wrist, the Synchron Poseidon wears identically to the Military, a watch that I owned and wore almost constantly for the summer of 2021 with plenty of dock jumping, cabin renovations, and general summer shenanigans. The dimensions make for a very nicely wearing watch, though I wouldn’t call the Poseidon thin. At a bit over 14mm thick, with the width and lug-to-lug making for a nearly square footprint, the Poseidon wears in a happily chunky manner.

If you want a Doxa comparison, the Poseidon is thicker and with more heft than a thin-case Doxa Sub 300, but much better balanced on my wrist than a 600T. While I wore one of the loaners on a NATO, I think a two-piece strap offers a better experience and keeps the weight of the Poseidon closer to your wrist. 

Combined with the thick and robust nature of the Isofrane rubber, the watch has a summery vibe that is similar to the Military and one that I rather like. It’s bright and fun – the sort of watch that will make you smile as the time pushes past five o’clock on the eve of a July long weekend.

Assuming that the only tight sleeve in sight is that of a wetsuit, I really like the way these cases wear as they offer an appropriate amount of bulk for a watch with ’70s dive watch inspiration, without being too much to wear for days on end. It’s not a dress watch or a small skin diver – it’s a handsome lump of steel that manages to very much feel like a piece of vintage dive-specific equipment.

The bezel is of the 120-click variety but has an extremely fine fitment with a crisp click, no wiggle or slop, and plenty of edge grip. With a fully graduated minute scale and lume for the numerals placed at every 10-minute segment, legibility is great and it’s the sort of bezel I’d be finding silly excuses just to use (what, you don’t ever time the interval between the low-battery chime from one of your home smoke detectors?).

I rather enjoyed my Military, so it’s of little surprise that I like the Poseidon, which Synchron is selling via pre-order for $999. After the pre-order, which ends on February 28th of this year, the standard price of $1,290 comes into effect. At $990, it’s something of a deal and I’d expect a lot of interest from the same folks that helped the Military sell out quickly when it launched on pre-order back in 2021.

Even at the full price (roughly the same as that of a solid Seiko Prospex model), it’s a good-looking 300m dive watch made in limited quantities as a collaboration with a storied dive equipment manufacturer and it has a higher-spec movement than we might expect for both the price point and format.

Much like with the Military, the Poseidon is something of a niche offering. But, for those within the folds of the correct niche, there is a lot of appeal, the pre-order pricing feels entirely realistic, and it’s always fun to see that logo back on the dial of a tough and colorful ’70s-themed diver.