Watches & Wonders 2026: Grand Seiko fans have spoken, and the brand has listened – the new Spring Drive U.F.A. Ushio 300 Diver is the dive watch we’ve been waiting for!
The world of dive watches is highly competitive. Ever since the introduction of the category (so to speak) in the early 1950s, the dive watch has become a staple of modern watch collecting, and given its highly versatile, robust nature, dive watches make for great daily wearers. I know I’ve always gravitated towards them, and always have had several in my collection at any given time.
While there are icons in the industry when it comes to dive watches, most notably Blancpain and Rolex, being the two brands that really pioneered the category, the variety and diverse nature mean there are so many other great dive watches out there to enjoy. Grand Seiko is one of those brands, and, being Grand Seiko, the Japanese brand has always applied its unique craftsmanship to its dive watch collection.
There were a few bug-bears, however, among the watch enthusiast community who thought the Grand Seiko diver was on the larger side and had a few design flaws, despite being nice. Well, Grand Seiko has considered all this feedback, and today it has unveiled the new Grand Seiko Diver, which, for lack of a better description, is a potential Sub killer!
The new Grand Seiko Spring Drive U.F.A. Ushio 300 Diver is the latest addition to the brand’s collection and replaces the old dive watch collection. With this new watch, Grand Seiko has upped the ante and created a very good diver. In a nutshell, the watch has been refined with a smaller, more ergonomic case, the dial has been cleaned up, and the bracelet and clasp have undergone major overhauls.
All this, and it is now rated to 300m, not 200m as the previous Evolution 9 Ushio Diver was, plus the new collection is made from High Intensity Titanium. Oh, and it now houses the Spring Drive U.F.A that debuted last year. That’s a lot ot unpack, so let’s run through it all.
A Refined And More Ergonomic Design
Let’s start with probably the biggest change. The new Grand Seiko Spring Drive U.F.A. Ushio 300 Diver has been shrunk down to a very wearable 40.8mm diameter, 48.5mm lug-to-lug and 12.9mm thick. This change means the new diver will fit a broader range of wrists, without hindering the overall feel and legibility of the dial. This is the smallest of any Grand Seiko diver’s watch to date.
The case and bracelet are made from High Intensity Titanium – Grand Seiko’s proprietary titanium alloy used for many of its cases and bracelets, engineered to be harder and visually brighter than standard titanium while remaining very light and corrosion‑resistant. So it is perfect for a drive watch. The lightness is also felt on the wrist, thanks to the case and bracelet made from the same material.
Speaking of the bracelet, this is also a major refinement from Grand Seiko. The bracelet has been overhauled to ensure a better wearing experience – now more refined and of better quality. In addition to this, Grand Seiko has developed a new clasp especially for this release. The clasp is much better machined, feeling more sturdy and reliable, and with more finesse. As these are dive watches, the clasp now comes with two independent extensions.
A 6mm comfort extension that can be let in and out via a micro-adjust slider on the inside. On top of this, there is an 18mm divers extension, so for those who want to take part in a little Scuba diving, can do so and have the watch fitted over a wetsuit. And if you are diving, there is a small slide lock on the clasp, so when locked, the push buttons are inoperable, and you can’t accidentally open it.
The Ushio Dial
Similar to the previous Evolution 9 Ushio Diver, this new variant is inspired by the waters around Japan. Ushio, meaning “tide” in Japanese, evokes the waters that surround the Japanese archipelago, a timeless source of inspiration in Japan’s culture and art. For the new collection, Grand Seiko has designed gradient blue and green Ushio dials, which take inspiration from the water – the blue takes you to the deeper ocean, whereas the green feels like you’re floating in the shallower waters off the beach, or on a reef.
When you see these dials in person in the daylight, they come to life. While similar, the green really stands out with little flecks of white coming through the dial, just like you would see with small white caps on the shallow waters on the beach. The blue is much deeper and has been crafted to emulate looking into the deeper water, and it does appear to do just that.
The date window at 3 o’clock has now gone, but Grand Seiko has kept the power reserve indicator on the dial at 7 and 8. This cleans the dial up a little and will be good news for those who like a no-date diver. The hour markers are now rectangular and large, all precision diamond cut to stand out, and the older style hands have turned more angular and modern. All this helps with dial legibility, and inside all is Seiko’s Lumibrite to give them an all-night glow.
The green dial is our pick of the two. The dial really pops and comes alive. Grand Seiko have done a fantastic job here, and the new, more modern hands and indices work incredibly well. Surrounding the dial is the 120-click unidirectional rotating dive bezel, with a dial matched blue or green ceramic insert, and a 60-minute dive scale.
A Movement Evolution
Inside the Grand Seiko Ushio 300 Diver is the Spring Drive U.F.A. Calibre 9RB1. Grand Seiko unveiled the Spring Drive U.F.A in the Evolution 9 “Ice Forest” models at Watches & Wonders last year in 2025. This was a revolutionary step up from standard Spring Drive movements, in the fact that it is accurate to ±20 seconds per year. Hence the name – Ultra Fine Accuracy of U.F.A for short. While that movement was the Calibre 9RB2, inside the new 300 Ushio Diver is the Calibre 9RB1, with the same accuracy rating.
Grand Seiko achieves this accuracy by vacuum sealing the crystal oscillator, which has been stabilised through a three-month aging process, together with the integrated circuit, minimising the influence of external factors such as temperature, humidity, static electricity, and light. Each oscillator’s frequency is measured at multiple temperatures, and the resulting data is programmed into the low-power integrated circuit to enable precise thermo-compensation.
The movement features a regulation switch that can be used during after-sales service to correct any divergences in accuracy that may occur over long periods of use. Running on the automatic Spring Drive system, the Calibre 9RB1 has a 72-hour power reserve and has a magnetic resistance of 4,800 A/m, or 60 gauss. I feel this is the only area where Grand Seiko could have improved, with many modern watches these days having a magnetic resistance of well over several hundred gauss, and in some cases, several thousand, given today’s gadget-driven lifestyle.
Initial Thoughts
When you have the chance to get hands-on with a watch well in advance of its release, it is both exciting and slightly frustrating at the same time. Exciting that you get to try on and play with the new watches, getting to know them in person for a period of time. But at the same time, if the watch happens to be a great release, with lots to talk about, conversely, you are not able to sing its praises to anyone for the immediate future. And this is where I found myself with the new Grand Seiko Spring Drive U.F.A. Ushio 300 Diver.
Talking to Grand Seiko, and coming back to my point at the very start of this article, I called this a potential Sub killer – referring to the Rolex Submariner. Why? Well, it goes basically head-to-head with the Sub in terms of the specs with regards to the size, depth rating and now, the redesigned bracelet and clasp (in fact, the sliding clasp mechanism is slightly easier to use than the Glidelock of the Sub), but it adds the High Intensity Titanium case and bracelet construction, the beautiful Ushio dial that gives the watches character.
Also, it now houses the Spring Drive U.F.A movement, ensuring the accuracy is ±20 seconds per year, which, if you work that out, is about ±1.6 seconds per month, far surpassing any mechanical, or quartz watch, for that matter, on the market. And the price. At A$17,700 each, these sit in the new normal for high-end dive watches, and right in between the Rolex Submariner and Submariner Date. And, you can buy them now!
References & Specifications:
| Feature | Specification |
|---|---|
| References: | SLGB023 – Blue / SLGB025 – Green |
| Dimensions | 40.8 mm diameter x 12.9 mm thickness x 48.5 mm lug-to-lug |
| Case Material | High Intensity Titanium, brushed and polished with a screw-down crown |
| Case Back | Screwed case back |
| Dial | Blue or green gradient “Ushio” textured dial. Diamond-cut markers and hands filled with Lumibrite. 120 click dive bezel with ceramic insert. |
| Crystal | Sapphire crystal with anti-reflective coating on the inner surface |
| Movement | Spring Drive U.F.A. Calibre 9RB1 automatic winding movement, accurate to ±20 seconds per year |
| Power Reserve | Approx. 72-hour power reserve |
| Water Resistance | 30 bar (300 metres) |
| Bracelet | High Intensity Titanium, brushed and polished with a push-button folding clasp, including 6mm comfort and 18mm dive extensions, plus locking mechanism |