1. The Grand Seiko Spring Drive U.F.A Ushio 300 is the brand’s most compact diver’s watch, with a 40.8 mm case.
2. It features the new Spring Drive U.F.A. Caliber 9RB1, claimed to be the most accurate Spring Drive movement with an annual error of 20 seconds.
3. The watch is available in two versions with blue (SLGB023) and green (SLGB025) dials, and includes a power reserve indicator.
4. It will be released in June 2026 with a retail price of $12,400 in the US and €12,500 in the EU.
Introducing the Grand Seiko Spring Drive U.F.A Ushio 300 Diver Watch
So, the new Grand Seiko Spring Drive U.F.A Ushio 300 Diver is finally here, and it’s getting a lot of buzz. This watch is said to be the smallest diver’s watch from the brand. It’s way more compact than other models, perfect for those who want a stylish yet functional piece. It made its debut at the Watches and Wonders 2026 event and is part of the new Evolution 9 series which is creating some excitement.
Design and Variants
The company is offering two different versions — one with a blue dial titled SLGB023 and another with a green dial called SLGB025. The name ‘ushio,’ which means tide in Japanese, points to the watch face’s wave pattern that mimics ocean tides. The whole watch is encased in a silver-colored titanium case, which is lightweight and durable. It comes with a matching bracelet, also in titanium. Interestingly, the watch doesn’t have a date display — just a simple, elegant three-hand dial. But, for functionality, it features a power reserve indicator located between 7 and 8 o’clock, adding a practical touch to its minimalist look.
Power and Precision
Now, let’s talk about the movement inside this beauty. The Ushio 300 uses the new Spring Drive U.F.A. Caliber 9RB1, which is a step up from the previous 9RB2 used in 2025. This movement is said to be Grand Seiko’s most precise Spring Drive watch yet. It boasts an impressive annual rate of just 20 seconds, which is about 3 seconds per month. The movement includes a self-winding system with manual-winding options, 33 jewels, and a power reserve of around 72 hours, making it very appealing for frequent travelers or enthusiasts.
Specifications and Release Info
This particular diver watch measures only 40.8 mm across, making it exceptionally small for a diver’s watch. It’s designed to be comfortable and less bulky, perfect for everyday use. The two models, SLGB023 and SLGB025, will hit the US market in June 2026 with a retail price of $12,400. Meanwhile, those in European countries can expect similar models at €12,500, both launching in the same month. It’s an exciting addition to Grand Seiko’s lineup for sure.














