Before Casio even announced it, the internet had already named it. The new G-Shock GMC-2500, part of the fully analog 2500 series, is being called the "CasioNaut" by collectors on Instagram, Reddit, YouTube, and watch forums. Casio officially unveiled the series on October 22, 2026, and it goes on sale in November. Here's everything you need to know, plus the story of how G-Shock fans keep giving these watches their own names.
The GMC-2500 is a fully analog G-Shock with no digital screen at all. Casio says the design reinterprets the DW-5000C, the very first G-Shock from 1983. It pairs a brushed stainless steel octagonal bezel with a bio-based resin case and strap, a brass dial with a sunray or honed finish, a small seconds subdial at 9 o'clock, and a three-cell date window at 3 o'clock.
The model shown here is the GMC-2500-1A: silver steel bezel, black sunray dial, and black resin strap, with the classic "G-SHOCK" and "PROTECTION" lettering on the bezel.
The nickname comes from the watch's resemblance to the Patek Philippe Nautilus. The softened octagon and the protruding "ears" on the case sides remind fans of Gérald Genta's famous 1976 design. Casio has never made that comparison itself. Officially, the brand points to its own DW-5000C as the inspiration.
The name took off in early September 2026, when the 2500 series briefly appeared on Casio's Japanese website before being pulled. Leaked pricing from G-Shock insider accounts on Instagram, an early hands-on video from YouTuber Gi-Shock-Go, and official teaser videos from G-Shock's own social accounts kept the "CasioNaut" conversation going for weeks before launch.
This isn't the first time the G-Shock community has renamed a watch. The GA-2100 became the "CasiOak" because its octagonal bezel looked like the Audemars Piguet Royal Oak, another Gérald Genta design. The nickname started in the Scottish Watches Facebook group and spread so widely that it now covers the whole 2100 family, including the metal GM-2100 and the solar Bluetooth GBM-2100.
That's part of what makes watch collecting fun. Nicknames like CasiOak, CasioNaut, the "Pepsi," the "Hulk," or the "Batman" don't come from marketing departments. They come from collectors. A good nickname tells you what a watch looks like, where it came from, and how the community feels about it, all in one word.
What would you call yours? Add your timepiece to your Rehaut 1775 collection, share it in Community, and let us know the nickname you've given it.
The 2500 series launches in Japan on November 7, 2026. In the US, it arrives in November at select retailers, gshock.casio.com, and the G-SHOCK Soho Store.
Early reactions online are mostly positive. Hands-on reviewers say the case wears smaller than its measurements suggest, and the GMC-2500 is about 2.6 mm shorter than the metal CasiOak, though about 1.1 mm thicker. Many praise the restrained dial and the clever date-window stopwatch.
There's also some debate. Longtime fans argue a "real" G-Shock should be digital, and some reviewers say the steel-bracelet GMC-2500D feels less refined than the resin-strap versions. Others point out the stopwatch maxes out at 31:59, and the pushers shouldn't be used underwater.
"CasioNaut" is the fan nickname for Casio's G-Shock 2500 series, which includes the GAC-2500, GMC-2500, and GMC-2500D. These are fully analog G-Shocks launched in November 2026.
Collectors say its rounded octagonal case and side "ears" resemble the Patek Philippe Nautilus. It's an unofficial nickname. Casio says the design is based on its own DW-5000C.
In the US, the GMC-2500 costs $280 to $300. The resin GAC-2500 is $145, and the steel-bracelet GMC-2500D is $350.
It goes on sale in Japan on November 7, 2026, and in the US in November 2026.
The CasiOak (GA-2100 family) has an analog-digital display and is nicknamed after the Audemars Piguet Royal Oak. The CasioNaut (2500 series) is fully analog, uses magnetic shock-release hands and a Multi-Mission Date window, and is nicknamed after the Patek Philippe Nautilus.
No. It runs on a CR1025 battery that lasts about two years, or about five years with the second hand sleep function on.
Yes. It's rated to 200 meters of water resistance. Just don't press the buttons underwater.
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