A Fan-Favorite Military Dive Watch Adds a Crowd-Pleasing New Case Size to the Lineup

Most things in human culture are cyclical, especially regarding style and watches.

A prevailing trend in 2025 has been the rise of smaller case sizes, on par with those of the 1950s through the early 1970s. Dress watches have led the way, but field and dive watches are catching up.

Marathon Watch

Marathon has met the changing, or rather, the regressing, times by releasing the OSAR-D (Original Search and Rescue – Date) dive watch in a 36mm case size. It is available with the original black dial and the Arctic dial released earlier this year.

While the Canadian watchmaker has produced plenty of 36mm watches before, the OSAR-D makes the most sense in that size. Even though it was introduced in the early 2000s, it is modeled after classic dive watches from the late 1950s and early 1960s, when most cases measured less than 40mm.

Marathon Watch

The alternating geometric indices, obelisk hands and dash minute track are reminiscent of vintage Seiko and Rolex designs.

From a pricing standpoint, Marathon lands much closer to the former than the latter. The Canadian watchmaker makes some of the most robust dive watches available in the $2,000 range, and the OSAR-D retains its 300m water resistance in the compact 36mm package.

A mirror image

For most of its history, Marathon was known primarily for its field and pilot’s watches. The GSAR (General Search and Rescue), which replaced the OSAR-D, is essentially a field watch with diver capabilities.

Marathon Watch

The OSAR-D was Marathon’s first watch to attract dive watch fanatics since the category boomed in the 2010s because, well, it looks like a dive watch. More specifically, it follows the template established by watches like the Fifty Fathoms and Submariner in the 1950s.

The beauty of the 36mm OSAR-D is that, like the long-established 36mm GSAR, it almost exactly matches the dial, bezel and case design of the 41mm version. Some elements are scaled down, but the hands, indices and date window remain the same size.

I find that tightening up the dial and eliminating some negative space improves the overall appearance. My only real complaint with the 41mm OSAR-D I’ve owned for nearly a year is that the hands feel too small for the watch’s size. The 36mm version balances everything out.

Marathon Watch

The dial’s most striking feature is the proprietary MaraGlo lume, which shines like it’s battery-powered in low light and doesn’t take much UV exposure to recharge. It blows away most Super-LumiNova formulas and is as effective as the tritium gas tubes used in most other Marathon designs.

Small but mighty

As a general rule of watch design and structural engineering, the smaller a watch case gets, the harder it is to achieve 300m water resistance.

Marathon takes a pragmatic approach. Rather than using fancy engineering tricks, it simply uses as much steel as needed to accomplish its goals.

Marathon Watch

The 41mm OSAR-D is a leviathan of a watch for its width, measuring 14mm tall, with a substantial portion of that coming from the bezel and sapphire crystal. Remarkably, the 36mm version shaves off a millimeter from its height.

At 13mm tall, it is still one of the bulkiest 36mm mechanical watches I’ve encountered, but it looks decidedly easier on the wrist than the 41mm. Again, these watches are built for practical use and just happen to have appealing dials.

The case’s standout physical feature is how large the crown looks, which remains the same size as the 41mm. The crown guard now takes up most of one side, spanning from two o’clock to four o’clock.

Marathon Watch

This downsized diver is powered by the same Incabloc shock absorber-equipped Sellita caliber SW200-1 a (the a denotes a date complication) as the 41mm version and Marathon’s entire Search and Rescue diver collection.

The 36mm OSAR-D and the 46mm version introduced simultaneously fill out the collection to match the options available in the GSAR. In that respect, the release was inevitable once the retro diver took off.

But, to me anyway, the smaller case size feels like a natural fit for this particular dial. At the same time, I concede that the 41mm makes more practical sense for anyone actually diving.

Availability and price

The Marathon OSAR-D 36mm is available now from Marathon for $1,600 on a steel three-link bracelet and $1,200 on a rubber pin-buckle strap.

Marathon Watch

Marathon OSAR-D 36mm

Specs

Case Size	36mm
Movement	Sellita caliber SW200-1 automatic
Water Resistance	300m

• $1,600 at Marathon (Arctic with bracelet)
• $1,200 at Marathon (Arctic with strap)
• $1,600 at Marathon (Black with bracelet)
• $1,200 at Marathon (Black with strap)

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