The Grand Seiko Evolution 9 Spring Drive U.F.A. Ushio 300 is a professional diver’s watch offered as the SLGB023 with a blue dial and the SLGB025 with a green dial. The case and bracelet are made of High-Intensity Titanium, which Grand Seiko says is about 30 percent lighter than stainless steel. The case measures 40.8 mm in diameter, 48.5 mm from lug to lug and 12.9 mm thick, with a 21 mm bracelet width, a unidirectional rotating bezel, a screw-down crown and a screw-down caseback. Water resistance is 300 metres, magnetic resistance 4,800 A/m, and the sapphire crystal has an anti-reflective coating on the inner surface. The Spring Drive calibre 9RB1 is self-winding with manual winding, has 33 jewels, about 72 hours of power reserve and a rated accuracy of ±20 seconds per year (±3 seconds per month), with a power reserve indicator on the dial.

The 9RB1 is a sport-oriented version of the calibre 9RB2 introduced in 2025 as Grand Seiko’s first Ultra Fine Accuracy movement. Its compact size allowed the smallest Grand Seiko diver case to date, compared with 43.8 mm for the earlier SLGA023. The gradient Ushio dial, named after the Japanese word for tide, uses a wave pattern that has featured on Grand Seiko divers since 2022. The bracelet has a locking clasp with three-step micro-adjustment of up to 6 mm and a diving extension of 18 mm. Both versions were announced in spring 2026 and went on sale in June 2026 at USD 12,400 (EUR 12,500).

Time+Tide’s Zach Blass said the 40.8 mm size removed the main reservation about earlier Grand Seiko divers and praised the case finishing, dial, legibility, accuracy and clasp, with only the lumed seconds counterweight as a minor complaint. Fratello’s Jorg Weppelink called them proper luxury divers and praised the size, titanium case, bracelet and accuracy, but found that the power reserve indicator crowds the dial and expected the large indexes and hands to divide opinion. Fratello readers largely liked the design, with several calling it the best Grand Seiko diver yet, while the most common criticism was the price compared with Rolex and Tudor. Both references are part of the regular Evolution 9 collection and are in production as of October 2026.