Seiko Unveils The Prospex SPB381, SPB383, And SPB385 — The First Mechanical GMT Divers In The Prospex Collection

We are all aware of Seiko’s great stream of new releases. Most of them are in line with what we know from the brand, but sometimes, Seiko manages to really shock us. Today, the brand expands its popular Prospex collection with three more models. But they are not just simply three additions to Seiko’s collection of dive watches. With the Prospex SPB381, SPB383, and SPB385, Seiko introduces the first three mechanical GMT divers to the Prospex collection. Two are regular additions to the permanent lineup, and one is a special Save the Ocean limited edition. You know I was all ears when these were revealed, so it’s time to find out more.

Seiko has jumped on the thundering GMT train running through the watch industry. It’s been only a couple of weeks since the brand released the solar-powered quartz GMT versions of its famous Sumo diver. I wrote the introduction article for the three models that came out. In the article, I alluded to the fact that I would have loved to see a smaller mechanical GMT diver added to the Prospex line. Well, we’re barely a month on, and my wish has been granted. Three new mechanical GMTs are based on the brand’s 1968 Diver’s Modern Re-interpretation. Are they the answer I had hoped for?

The Seiko 1968 Diver’s Modern Re-interpretation

Seiko introduced three different models, of which two are regular editions. The SPB381 has a green dial, and the SPB383 has a black one. The third model is the SPB385, a special Save The Ocean limited edition with an ice-blue dial. For those of you familiar with the Seiko 1968 Diver’s Modern Re-interpretation, you know it looks like the Marinemaster. I think it’s sometimes even confusing how much the two are alike. Not that I have a problem with it because the sharp angles of the Marinemaster case are absolutely stunning. And that’s why I also love the modern interpretation of the 1968 diver.

The Seiko Prospex SPB185 and SPB187

But these two new models are not just simply divers. The added GMT functionality created a totally different beast. As some of you will know, I have a thing for GMTs, and I love Seiko’s 1968 Diver’s Modern Re-interpretation. Some of the variations we have seen look amazing and could easily be a great next Seiko diver for me. Especially the SPB185 and SPB187 come to mind, which were two of the most popular releases of 2020. Additionally, the SLA055 and SLA057 from late 2021 were two more great releases. Comparatively, they were on another level, though. They had better movements, different dials, different placement of elements, and very different prices too. And the new GMT models? While they follow the line of the SPB185, they take influences from both.

The regular Seiko Prospex SPB381 and SPB383

So let’s zoom in on the two regular models first. As said, the SPB381 and SPB383 have green and black dials, respectively. I love seeing both dial colors as they make for a great-looking diver. Additionally, both colors allow for a similar gold-colored GMT hand. It is one of the two elements indicating that these are not just your normal dive watches. The second is the obvious gold “GMT” text on the dials of both watches. Seeing both watches begs the question of whether these models really stand out versus their non-GMT counterparts. But the immediate question back would be: would you want them to?

Seiko reminds us, first and foremost, that these are GMT versions of their divers. They are not completely different GMT watches. Therefore, it makes it easy to make them part of the Prospex series as full-fledged divers that are equipped with a 24-hour scale on the rehaut of the dial instead of a 24-hour bezel. The diving bezel remains intact, as does most of the watches’ looks. But the bezel has been slimmed down to increase the dial’s size and integrate the GMT elements neatly.

Let’s line up some specs of these models

So if these watches are divers first, let’s remind ourselves of some specs. All three models have a 42mm stainless steel case in line with the regular diver. The case is water resistant to 200 meters and comes in at 12.9mm thick. It makes these versions 0.4mm thicker than the regular models. The watches come equipped with a ceramic bezel insert and a stainless steel bracelet with a folding clasp, a security lock, and a diving extension. One thing that is in line with the more expensive models I referred to earlier is the date placement. The date window is placed between 4 and 5 o’clock, with the crown placed slightly above the 4 o’clock position. As Lex explained in his review of the SLA055 and SLA057, the misalignment is subtle, but once seen…

The Seiko Prospex SLA057J1 and SLA055J1

Looking at the dial, you will see that it is in line with the regular models. The main difference is the 24-hour scale on the rehaut with the accompanying 24-hour hand. Therefore, these pieces still look very much like dive watches. The 24-hour scale is very subtle, with numbers for the uneven hours and triangles for the even hours. The GMT hand is very straightforward but nicely executed, standing out enough to be practical while blending in enough not to mess with the diver’s character of the watch.

The new Seiko caliber 6R54

Inside the 42mm case, Seiko equips all three of the watches with its new in-house Seiko caliber 6R54. The automatic GMT movement operates at 21,600vph and delivers 72 hours of power reserve. The movement lets you independently set the GMT hand of the watch in one-hour increments. It makes the new caliber a caller GMT and not the much-wanted flyer GMT. We have talked a lot about whether you would absolutely need a flyer GMT, and it’s a matter of personal preference. We can say that at the €1,700 price point that these new models come in at, we will see more and more flyer GMTs over time.

The Save the Ocean Limited Edition SPB385

The third model is the Seiko Prospex Save the Ocean Limited Edition SPB385. It was created to commemorate the 110th anniversary of Seiko’s first wristwatch, the famous Laurel. To celebrate that, Seiko created a special texture ice-blue dial for the SPB385. The dial was inspired by the polar glaciers of the Arctic and Antarctic, where famous explorers like Naomi Uemura wore Seiko watches.

The watch has the same size and technical specs as the two regular models. Besides the special dial, the watch also comes with an extra gray NATO strap along with the stainless steel bracelet. The NATO straps are made from recycled plastic bottles and were created using the traditional Japanese Seichu braiding technique. The watch is part of the Save the Ocean series that supports the mission to contribute to a greater understanding of the world’s oceans and their preservation. This SPB385 model joins the 1968 Diver’s Modern Re-interpretation SPB299 that Nacho wrote about last year, which was also part of the same series.

Are these true divers? Or are these true GMTs?

My first thought is that I would love to see them in the metal and take them for a spin. The regular SPB381 and SPB383 will be available in June 2023 for €1,700. The Save the Ocean limited edition SPB385 will see a production run of 4,000 pieces and will cost €1,900. We hope to get these watches in for a hands-on review before they go on sale and give them some much-wanted wrist time. After seeing the first pictures, I am very curious to learn more.

I love the idea of a GMT diver. But I also love the modern interpretation of the 1968 diver as a clean, modern-day dive watch, first and foremost. Don’t get me wrong; I love how Seiko integrated all the GMT elements neatly so as not to mess up the dive-watch look. It creates a clean aesthetic and adds the great GMT functionality I love. Could this be potentially even better than the regular diver? This is exactly why I would love to find out more about these three first mechanical Seiko Prospex GMT models.

For more information, check the official Seiko website. Let us know your thoughts on these three new Seiko Prospex GMTs in the comments section too!