Grand Seiko SLGB023 and SLGB025 Ushio 300 Diver: Are These The GS Divers Enthusiasts Wanted?

Grand Seiko makes some incredible watches, but I’ve always found its divers slightly tricky.

Not bad tricky. Far from it.

Grand Seiko divers have always had presence, capability and that unmistakable GS quality. But for my wrist, many of them have felt a little on the large and chunky side. Impressive? Absolutely. Easy for me to picture wearing every day? Not always.

That’s why the new Grand Seiko SLGB023 and SLGB025 Ushio 300 Divers immediately caught my attention when I saw them at Seiko UK.

I was there to see some of Grand Seiko’s latest Watches and Wonders 2026 releases, and these two divers were among the pieces that really stood out during the visit. That always helps, doesn’t it? It’s one thing to read a list of specs online. It’s another to hold the watch, feel the weight, see the dial under real light, and hear why certain decisions were made.

These are still serious dive watches. That much is obvious.

But they felt smaller, lighter and much more wearable than I expected.

And honestly, that might be the most important thing about them.

A Grand Seiko Diver That Finally Feels More Wearable

The first thing that struck me was the size and weight.

On paper, the dimensions already sound more approachable. The case measures 40.84mm across and 12.94mm thick, with a 300m Air Diver rating. That puts it in a much more wearable place than some of the larger Grand Seiko divers we’ve seen before.

But it was the feel in the hand and on the wrist that really stood out.

These watches use Grand Seiko’s high-intensity titanium, and while I own a few titanium watches myself, the lightness of these still surprised me. There was a proper sense of quality there, but without the heaviness you might expect from a serious luxury diver.

That balance is important.

A dive watch should have wrist presence. I want it to feel capable, solid and ready for use. But I don’t want it to feel bulky, intrusive or like it’s constantly fighting my wrist.

The Ushio 300 Diver gets that balance right.

It still feels like a proper sports-focused diver, but it doesn’t feel oversized for the sake of it. It has that presence you want from a dive watch, just without the unnecessary heft.

For me, that makes a big difference, especially if I’m wearing it daily.

Grand Seiko SLGB023 and SLGB025 Key Specs

Before getting too carried away with how these felt in person, it’s worth laying out the key details.

• References: SLGB023 and SLGB025

• Collection: Grand Seiko Evolution 9 Collection

• Case material: High-intensity titanium and ceramic

• Case size: 40.84mm diameter

• Thickness: 12.94mm

• Lug width: 21mm

• Water resistance: 300m Air Diver

• Crystal: Sapphire crystal with anti-reflective coating on the inner surface

• Bracelet: High-intensity titanium

• Clasp: New locking extension diving clasp with micro-adjustment

• Movement: New 9RB1 Spring Drive UFA

• Accuracy: ±20 seconds per year

• Power reserve: 72 hours

• Price: £10,500

The headline spec is obviously the 9RB1 Spring Drive UFA movement, but the whole package matters here. The titanium case, the slimmer profile, the new clasp, the no-date layout and the 300m diver rating all play their part.

This isn’t just Grand Seiko making a very accurate watch and putting it in a dive case.

It feels more considered than that.

Still A Serious Tool Watch

One of the dangers with luxury dive watches is that they can become a little too polished for their own good.

You know the type. We won’t mention any names!

They are technically dive watches, but really they’re more at home under an office cuff than anywhere near the sea.

The Grand Seiko Ushio 300 Diver doesn’t give me that feeling.

Yes, the dial finishing is beautiful. Yes, the titanium case feels premium. Yes, the overall execution has that Grand Seiko refinement. But you’re under no illusion that this is still a serious diver.

The watch has 300m water resistance, a unidirectional rotating bezel, strong legibility, LumiBrite, a screw-down crown and a proper dive-watch clasp. It looks and feels ready to be used as a sports watch.

That’s where I think Grand Seiko has done something quite clever here.

The Ushio 300 Diver doesn’t feel like a tool watch trying to be basic, and it doesn’t feel like a dress watch pretending to be rugged. It sits somewhere in the middle: premium, refined and beautifully finished, but still purposeful.

That’s not always an easy line to walk.

A More Practical Grand Seiko Diver

There were a few details talked through during the visit that made these watches feel more practical than they might first appear.

The ceramic bezel insert sits within the titanium bezel construction, which gives it a more protected feel than if it were simply sitting proud and exposed. That’s the kind of thing most of us probably wouldn’t notice straight away, but once it’s pointed out, it makes sense on a watch that’s meant to be used as a diver.

The clasp is another big one.

Grand Seiko has given these watches a new locking extension diving clasp with micro-adjustment. That might not sound as exciting as a textured dial or a new movement, but if you actually wear your watches, clasp adjustment matters.

A lot.

Wrists change during the day. Heat, cold, movement, travel, exercise, all of it makes a difference. On a sports watch, and especially on a diver, a good micro-adjustment system can be the difference between a watch you like and a watch you actually enjoy wearing.

This is one of those areas where collectors have been asking for more from Grand Seiko for a while, so it’s good to see it being addressed properly here.

Blue Or Green? Head Says Blue, Heart Says Green

The SLGB023 comes with the blue dial, while the SLGB025 brings the green.

Choosing between them would be a very nice problem to have.

It reminded me of the same issue I’ve had with other brands, especially Omega and G-SHOCK. Do you go blue because it’s classic, versatile and easy to wear? Or do you go green because it feels a little more special, even if it might be slightly harder to match?

My head probably says blue.

The blue SLGB023 is the safe choice in the best possible way. It gives you that classic dive-watch feel, and the darker tone works beautifully with the idea of deep ocean water. It feels serious, rich and very easy to imagine wearing often.

But my heart was drawn to the green SLGB025.

The green is a slightly lighter shade, and in person it looked beautiful against the titanium. It had a bit more life to it, without tipping into anything loud or flashy. The lighter colour also made the dial texture slightly more apparent to my eye, which helped it stand out.

So if I had to choose?

I think I’d go green.

It’s the less obvious option, but that’s probably why I liked it so much.

The Ushio Dial Pattern Really Works

The dial pattern is a big part of what makes these watches feel like Grand Seiko.

The name Ushio means tide, and the dial texture is inspired by the seas and strong currents around the Japanese archipelago. That could easily sound like marketing fluff, but in person the pattern genuinely adds something to both watches.

On the blue SLGB023, the dial gives a sense of depth. It feels darker, deeper and more ocean-like. There’s movement there, but it’s not busy.

On the green SLGB025, the lighter shade gives the pattern a slightly different character. It feels more like shallower water catching the light. The texture was more obvious to me on the green, and that was part of why I found it so appealing.

Both dials elevate the watches.

That’s the key thing.

They give the Ushio 300 Divers that premium Grand Seiko feel, but they don’t turn them into fancy desk divers. They still feel like serious dive watches. The texture adds character and depth, but the basic job of being clear, legible and functional is still there.

That’s exactly what I want from this kind of Grand Seiko.

It’s also part of the wider appeal of the brand. I’ve written before about Grand Seiko’s nature-inspired dials, and this is another example of Grand Seiko taking a natural idea and turning it into something you can actually enjoy on the wrist.

That same seasonal, nature-led approach is also what made the Grand Seiko Sakura-Kakushi and Sakura-Tukiyo limited editions so interesting. Different watches entirely, of course, but the appeal comes from a similar place: texture, light and a dial that rewards a longer look.

Grand Seiko Made The Right Call Going No-Date

I love that Grand Seiko went no-date with these.

For me, that’s one of the biggest wins.

I don’t like a dial to feel too cluttered, especially when the dial itself is such a key part of the watch. Add a date window in the wrong place and suddenly the whole thing can feel interrupted.

With these watches, the Ushio dial pattern deserves space.

A date window would have taken something away from that. It might have been useful, but I think it would’ve detracted from the balance.

There’s still a power reserve indicator on the dial, which I know will divide opinion. Grand Seiko power reserve displays often do. Some people love them. Some would rather they were hidden away on the back.

On these watches, it didn’t bother me.

On the wrist, the power reserve felt well balanced and didn’t spoil the dial. It also makes sense on a diver, where being able to check remaining power quickly is actually quite useful.

Would the dial look even cleaner without it? Maybe.

But did it ruin the watch for me? Not at all.

UFA Spring Drive Accuracy Is The Big Technical Story

The movement inside these watches is the new Grand Seiko 9RB1 Spring Drive UFA calibre.

UFA stands for Ultra Fine Accuracy, and this is where the Ushio 300 Divers become more than just a pair of nicely sized titanium dive watches.

Grand Seiko rates the movement to ±20 seconds per year.

Per year.

That’s the kind of figure that makes you stop for a moment.

Now, we need to be sensible with comparisons. If you move into quartz, digital, GPS or radio-controlled watches, accuracy becomes a very different conversation. Someone could quite fairly say that a G-SHOCK can be incredibly accurate, tough and much cheaper.

But that’s not really the same buyer or the same category, is it?

For a mainspring-powered luxury diver, this level of annual accuracy puts the Grand Seiko UFA movement in a different league.

That’s what makes it feel special.

Spring Drive has always fascinated me because it gives you the mechanical feel of a mainspring-powered watch, but with that smooth glide and incredible accuracy. The UFA movement takes that idea even further.

And in a serious 300m diver, it gives these watches a real point of difference.

A lot of luxury divers are competing on heritage, case shape, bracelet quality, brand status or familiar design. Along with those things, Grand Seiko is bringing something else to the table here.

Accuracy.

And not in a small way.

The 9RB1 Movement Feels Made For This Watch

There are a couple of small technical details around the 9RB1 movement that are worth calling out.

First, the movement features a redesigned oscillating weight, which Grand Seiko says is there to increase durability for a sports watch. Again, that’s not the sort of detail that gets everyone excited at first glance, but it matters. This isn’t a dressy movement dropped into a rugged case and called a day. It has been thought through as part of the wider watch.

Second, the movement also features what Grand Seiko calls its Shinshu Frost Finish, which feels like a nice touch even on a serious diver. You may not be staring at the movement all day, especially with the practical demands of a 300m dive watch, but I like that Grand Seiko still cares about those details.

That’s the brand, really.

The practical stuff matters. The hidden details matter too.

I had the same feeling after visiting the Grand Seiko UK service centre. The more you see of the brand behind the scenes, the more you realise how much thought goes into the parts most people never really think about.

High-Intensity Titanium Matters More Than You Might Think

The titanium case is one of the reasons these watches work so well on the wrist.

Grand Seiko’s high-intensity titanium isn’t just about making the watch lighter, although that’s obviously a big part of the appeal. The material is also corrosion-resistant and harder than pure titanium, while still giving Grand Seiko the ability to create a bright finish with polished surfaces.

That last part matters.

Some titanium watches can look a little dull or grey. These didn’t have that feeling. They still had enough brightness and quality to feel like Grand Seiko, but with the comfort and lightness you want from a sports diver.

That’s a big part of why the watch worked for me.

It didn’t feel like Grand Seiko had simply made a smaller diver. It felt like the case material, size, dial and movement were all working together.

The Bracelet Is Better, But I’d Go Rubber

The titanium bracelet felt great.

Light, comfortable and exactly in keeping with the feel of the watch. The new micro-adjustment system is also going to make a lot of people happy.

That matters because bracelet adjustment has been one of those areas where Grand Seiko hasn’t always been as strong as some collectors would like. On a sports watch, especially a diver, easy adjustment isn’t just a nice extra. It makes the watch easier to live with.

So yes, the improved clasp is a very welcome feature.

Personally though, I kept coming back to the colour-matched rubber straps.

That’s probably where I’d go with one of these.

On a proper sports diver, especially one this light, the rubber strap option just makes sense to me. It keeps the watch focused, casual and ready to wear. It also leans into the idea that this isn’t just a luxury object, but something you can actually use and enjoy without overthinking it.

The bracelet is good.

But for me, the rubber strap might be the sweet spot.

The Price Is Serious, But It Makes Sense

The Grand Seiko SLGB023 and SLGB025 are priced at £10,500.

That’s serious money.

There’s no point pretending otherwise.

At that price, these watches are sitting in a very competitive part of the market. You can buy some excellent dive watches for this kind of money, and anyone shopping around this level will have a lot of options.

Omega Seamaster. Rolex Submariner, if you can get one. Blancpain Fifty Fathoms. Tudor Pelagos models at a lower price. Plenty of others too.

So Grand Seiko has to bring something genuinely different.

And I think it does.

If you want a titanium luxury diver, the list of rivals gets smaller. If you want Grand Seiko finishing, it gets more specific again. If you want a mainspring-powered luxury diver with this level of annual accuracy, I honestly can’t think of anything that comes close unless you move into quartz, digital, GPS or radio-controlled watches.

Then add the dial work, the 300m water resistance, the more wearable case size, the new clasp and the overall execution, and the price starts to make sense.

That doesn’t make it a steal.

But I don’t think it needs to be.

These feel competitive, just not cheap. And honestly, I’m fine with that.

Different buyers will weigh those things differently. Some will care most about brand recognition. Some will want the obvious choice. Some will want the watch everyone else already knows.

But if accuracy, finishing, titanium construction and something a little less predictable matter to you, the Ushio 300 Diver has a very strong argument.

Who Is The Grand Seiko Ushio 300 Diver For?

I think these watches could appeal to two groups.

The first is existing Grand Seiko fans.

If you already love the brand but have found previous Grand Seiko divers a little too large or heavy, this could be the one that finally makes sense. It still feels like a proper GS diver, but now with a size and weight that make it much easier to imagine wearing regularly.

The second group is more interesting.

I genuinely hope these watches bring new people into Grand Seiko.

There will always be buyers looking at the usual luxury diver options. Submariner. Seamaster. Black Bay. Fifty Fathoms. All great watches in their own way.

But not everyone wants the obvious choice.

Some people are tired of waiting lists. Some people want something that feels more individual. Some people want a watch that still has serious capability, but with a different kind of character.

That’s where the Ushio 300 Diver could work really well.

I’d genuinely love to bump into someone wearing one of these. Not because they picked the expected option, but because they chose something a bit different, beautifully made and quietly special.

That tells you something about a collector.

How It Fits Into Grand Seiko’s Direction

What I like about the Ushio 300 Divers is that they feel like Grand Seiko listening without losing itself.

Smaller case? Yes.

Lighter titanium build? Yes.

No-date dial? Thankfully, yes.

Improved clasp? Finally, yes.

But it still feels like Grand Seiko. The dial has character, the finishing is strong, the movement is genuinely interesting, and the watch doesn’t feel like it’s trying to copy the usual luxury diver formula.

That’s important.

Grand Seiko is at its best when it feels confident enough to do things its own way. I felt that with the Grand Seiko SLGH027 Mountainscape, and I feel it again here.

The Ushio 300 Diver isn’t trying to be a Submariner. It isn’t trying to be a Seamaster. It’s trying to be a Grand Seiko diver that more people can actually imagine wearing.

That feels like the right move.

The Wider Seiko Appeal

One of the reasons I keep coming back to Seiko and Grand Seiko is the sheer range of what they do.

At one end, you have approachable daily watches and proper tool watches. At the other, you have Grand Seiko pushing finishing, accuracy and movement innovation in a way that feels very much its own.

That’s why watches like the King Seiko VANAC Tokyo Midnight interest me too. It’s a very different watch to the Ushio 300 Diver, of course, but it shows how Seiko can lean into design, character and enthusiast appeal without simply following the obvious route.

And that’s what I like here as well.

The Ushio 300 Diver feels like a proper luxury diver, but it still feels distinctively Grand Seiko.

Grand Seiko SLGB023 and SLGB025 FAQ

What is the difference between the Grand Seiko SLGB023 and SLGB025?

The main difference is the dial colour. The SLGB023 has a blue Ushio dial, while the SLGB025 has a green Ushio dial. Both watches share the same case size, titanium construction, 300m water resistance and 9RB1 Spring Drive UFA movement.

Is the Grand Seiko Ushio 300 Diver titanium?

Yes. The SLGB023 and SLGB025 both use Grand Seiko’s high-intensity titanium, along with ceramic in the bezel construction. The titanium helps keep the watch light and comfortable while still feeling like a serious sports diver.

How accurate is the Grand Seiko SLGB023 and SLGB025?

Both watches use the 9RB1 Spring Drive UFA movement, which Grand Seiko rates to ±20 seconds per year. For a mainspring-powered luxury diver, that’s an exceptional level of accuracy.

Does the Grand Seiko Ushio 300 Diver have a date?

No. Both the SLGB023 and SLGB025 have no-date dials. Personally, I think that’s a great choice because it keeps the Ushio dial pattern cleaner and more balanced.

How much is the Grand Seiko SLGB023 and SLGB025 in the UK?

The UK RRP for both models is £10,500.

Does the Grand Seiko Ushio 300 Diver have micro-adjustment?

Yes. These models feature a new locking extension diving clasp with micro-adjustment, which should make the bracelet easier to live with day to day.

Final Thoughts

The Grand Seiko SLGB023 and SLGB025 Ushio 300 Divers feel like a big step in the right direction.

For me, the biggest change is wearability.

Previous Grand Seiko divers have often impressed me, but they’ve also felt a little too large and chunky for my wrist. These felt different straight away. Smaller, lighter and easier to imagine wearing, but still with proper dive-watch presence.

The dials are superb. The titanium case works beautifully. The no-date layout is a great call. The power reserve didn’t spoil the balance. The improved clasp is a welcome upgrade. And the UFA Spring Drive accuracy gives the watch something genuinely special.

Would I pick blue or green?

My head says blue.

My heart says green.

And if pushed, I think I’d go green.

At £10,500, these watches aren’t cheap, and they aren’t trying to be. But if I was in the market for a premium diver, one of these would now be very high on my list.

The size finally works for me. The dials are excellent. The titanium makes them properly wearable. And that level of accuracy feels like a major feat of watchmaking.

Now I just need £10,500.

You can check out the full range from Grand Seiko here Grand-Seiko.com