Grand Seiko Spring Drive U.F.A. Ushio 300 Diver watches

Has Grand Seiko created the ultimate luxury dive watch? That’s a common view since the brand unveiled the SLGB023 and SLGB025 last April. In our view, these two sporting references aim well beyond their product category.

The new watches’ design mimics the Evolution 9 case, and its Spring Drive U.F.A. calibre delivers otherworldly engineering. Since its 2025 debut, the ultra-fine-accuracy movement has steadily extended to other models. Introduced last April, the Ushio 300 Diver is its dive-watch counterpart.

Spring Drive U.F.A. Ushio 300 Diver

When Grand Seiko introduced the Evolution 9 collection, I initially struggled to understand its purpose: evolution or replacement?

Probably both. The Grammar of Design—Grand Seiko’s design bible—sets strict aesthetic principles and boundaries, yet this collection has shown unexpected creativity.

The Evolution 9 dive watches have since abandoned the brand’s original mechanical and Spring Drive diver’s watch design.

A smooth symmetrical case, a recessed 3 o’clock crown, and extensive use of High–Intensity Titanium have given Grand Seiko’s divers a sportier, more distinctly “European” character than their predecessors.

The Voice of Customer

I like to imagine the development team asking: “What does an enthusiast look for in a dive watch, and what sets ours apart?”

Balanced proportions may draw an enthusiast in, but outstanding engineering and build quality must deliver on that promise. Grand Seiko’s obsessive attention to detail is key.

The Evolution 9 Spring Drive U.F.A. Ushio 300 Diver SLGB023 “Ushio Blue” and SLGB025 “Ushio Green” embody these principles in a surprisingly compact package, despite their big capabilities.

Their symmetrical case measures 40.8 mm across and 12.9 mm thick—compact for a 300m–rated professional dive watch.

Neither is engineered for saturation diving, which would require a different build; excellent finishing and a close-to-50mm lug-to-lug measurement complete a well-built, highly wearable design.

The designers have kept several features from earlier Evolution 9 divers: deep grooves for gripping the crown and bezel—the latter offering 120 beautifully precise, smooth clicks—and superb Zaratsu finishing on the High-Intensity Titanium case and bracelet. This is arguably the finest polishing one could ask for on this metal in this category.

The new clasp joins the diver’s watch collection.

Built for active use, the Evolution 9 Spring Drive U.F.A. Ushio 300 Diver is the first dive watch to receive a diver-oriented version of the original U.F.A. clasp. It features a dual-push-button release and a micro-adjustment system offering 6 mm of extension for everyday wear.

It also adds extra protection: a snap-lock safety catch, operated via the GS logo, helps prevent accidental opening.

Grand Seiko took its time to listen to the community’s feedback before designing a clasp that ticks all the boxes: sturdy, easy to use, and equipped with a proper micro-adjustment mechanism.

Inside the compact, well-proportioned case sits the Spring Drive 9RB1 calibre, a take on the original 9RB2 with a power-reserve gauge on the dial. This makes it the world’s most accurate luxury dive watch.

The U.F.A. movement alone is worth the asking price, but you need a solid understanding of watchmaking and Spring Drive technology. Only then can one grasp what it takes to achieve an accuracy of ±20 seconds a year—meaning perfect timekeeping in everyday use.

Final thoughts

Perfection is a target you look for but never achieve. Still, Grand Seiko comes remarkably close here. With the Evolution 9 Spring Drive U.F.A. Ushio 300 Diver, the brand has set an exceptionally high bar for premium watches.

However, the designers have given the dials similar attention. Both colours feature the Ushio pattern—Japanese for “tide”—and broad indexes filled with LumiBrite for a strong glow in the dark.

At €12,500, the asking price is undeniably significant, but it reflects what Grand Seiko delivers. The brand has set a technical benchmark for its rivals and shown just what you can buy in this price bracket.

Although the collection comes exclusively in titanium—a lightweight, hypoallergenic metal ideally suited to a sports watch—I hope Grand Seiko considers an Ushio in Ever–Brilliant Steel.

The Ushio 300 Divers sit in a broader arena, as much a luxury sports watch as a professional diver, without ever entering into tool-watch territory. That versatility makes this Grand Seiko one of 2026’s most compelling releases.

(Photo credit: Horbiter®)