When Seiko Sumos Fly: Seiko Introduces a Pair of Solar Diver GMTs Ready for Your Next Adventure Abroad

It seems to me that more recently, Seiko has had “travel” on the mind. I say that based on the steadily increasing incorporation of the GMT complication within their more entry-level products. Last year we finally saw a GMT movement make its way into the Seiko 5 sports line with the SSK GMT and we all went bananas for it. I mean how could we not? It’s a travel ready watch packaged into a familiar and beloved Seiko design at a very reasonable price point. Their Prospex line however, has more experience with jumping time zones as it already provides multiple models with a fourth hand like the compass bezel equipped SNR025 and the more traditional looking traveler with the SNR033. Last week, Seiko announced a new GMT addition to the Prospex range and much to our excitement, they’re taking a page out of their SSK GMT release by throwing in a GMT complication into a familiar case silhouette.

The new models we’re referring to are the SKF001J1 and the SFK003J1. Essentially what we have here is the Seiko Sumo with an added feature of a GMT hand via a solar powered quartz movement and a dial modification to accommodate the additional hand. The Seiko Sumo, which gets its nickname from its portly case and the signature twelve o’clock marker resembling the “Mawashi” of a competing sumo wrestler, got several updates from last year’s release including a ceramic bezel, super-hard coating, new dial design and a refresh to the accompanying stainless steel bracelet. The SFK001J1 and SFK0031J1 retains all of these upgrades. But now the Seiko Sumo isn’t just ready for diving, it’s ready to do some flying as well.


The two dial variations have a color matched elapsed time bezel and are anchored by their orange accents that highlight the GMT feature. The SFK001J1 is your blue dial variant. The dial has a texture decoration that resembles that of thread stitch pattern. The lines cross in and out of one another as they move across the dial, and on the SFK001J1, are topped with a sunburst effect. Every piece of dial furniture is applied and that includes the logos, markers, and the small numerals positioned in between the hour markers. The rehaut displays a minute track and a split colorway demarcating daytime hours with an indigo colorway. The Sumo handset still remains, but this time it has company with a sharp GMT arrow hand that gets a hit of a saturated orange.

The SFK003J1 is your green dial variant. Like the SFK001J1, it has the orange GMT accents and a split tone rehaut, but the daytime hours are highlighted by a kermit green. The green dial is more muted in nature, as it doesn’t have the sunburst effect like its cohort. The addition of the GMT features here are subtle and well balanced, in my opinion. They’re present and visible just enough so that they’re noticeable and more importantly, usable when you need them, but still remain cohesive, and it doesn’t take away from the Sumo aesthetic.

Another feature of the dial is its translucent layer which gives way to any sort of light and charges the Seiko in-house 5K65 solar quartz movement. That’s the other major difference here. There’s no mechanical movement in sight, so expect a ticking of the seconds hand as opposed to a smooth sweeping hand. What you do get in return with the 5K65 movement is an independently adjustable 12 hour hand making this iteration of the Sumo a traveler or flyer GMT. In addition to the new GMT feature, the 5K65 is also built-in with a date function and a quick-start function which allows the watch to start within seconds after being exposed to light. Expect the movement to run +/- 15 seconds per month which is fairly standard among Seiko’s quartz movements of this caliber.

When it comes to the case, the SFK001J1 and SFK003J1 are big boys. They’re nicknamed the Sumo after all. Layered with Seiko’s proprietary super-hard coating, the case measures 45mm in width, 13.2mm in thickness and a very long 51.8mm lug to lug. For the most part, the case proportions match up with the 2022 Sumo, except for the thickness, as these two models are about 1mm thicker. The large case hugs around the bezel and a side view of the case shows the bezel nestling in, and only fully exposing the bezel grip at the top and bottom of the case. There’s an alternating use of brushed and polish finish on the case, with the latter being used in an interesting way. The case sides get a heavy dose of polish as it widens within the curvy midcase, but its the hint of polish on the inner portion of the lugs that add a different dynamic to the overall case aesthetic.

As I mentioned above, the Seiko released last year got an updated steel bracelet, and that’s what we have here. The design leans more towards an oyster design, and is refined by the use of polish along the sides of the center links. The bracelet is secured by a locking three-fold clasp and is also equipped with a dive extension.

As far as GMTs go, this is by far my favorite format. A Diver GMT. Emphasis on the word diver, as it’s a dive watch first and a travel watch second, as opposed to a designated travel watch with added dive watch features. I prefer to have all of my GMT settings relegated to the dial and preferably would like some sort of legible 24 hour scale. We get that here with the SFK001J1 and SFK003J1, plus a split tone rehaut which not only adds more to the GMT feature, but feels very much a part of the dial design. This leaves the bezel open to using a more practical elapsed time bezel. You get both the GMT functionality AND a dive watch with 200 meters of water resistance.

Seeing a Seiko Sumo use a solar quartz movement instead of a mechanical movement might take some getting used to. But I fully support Seiko going this route. I currently own the Seiko SNE573 Solar Diver and the fact that it’s a solar watch is already enough to refresh the way I look at my own watch collection. It always has the right time, barring any periods of non-wrist time that pass Daylight Saving Time. And changing out a battery on a regular basis in a quartz movement is one less thing to worry about with a solar quartz movement.

The Seiko Prospex Sumo Dive GMT SFK001J1 and SFK003J1 retail at a very approachable $805 after the conversion. That’s $50 less than the regular Seiko Sumo with a 6R35 automatic movement. Bear in mind with these two models, although you are getting solar quartz movement, you do get a GMT capable watch with an independently adjustable hour hand. A fair trade-off if solar quartz isn’t your jam. It’s also worth noting that Seiko announced two other colorways in this Sumo iteration that lean more into the traditional aesthetic – the SBPK003 which sports a black dial, black bezel and red GMT accents, and the SBPK005 which has a black dial and a pepsi bezel (credit here to @plus9time on Instagram). It appears that the SFK001J1 and SFK003J1 are only available through Seiko retailers outside of the United States. As for the aforementioned SBPK003 and SBPK005, you’re going to have to stay tuned to the Seiko space for more information. Seiko

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Thomas is a budding writer and an avid photographer by way of San Diego, California. From his local surf break to mountain peaks and occasionally traveling to destinations off the beaten path, he is always searching for his next adventure, with a watch on wrist, and a camera in hand. Thomas is a watch enthusiast through and through; having a strong passion for their breadth of design, historical connection, and the stories that lie within each timepiece.