Introducing Seiko’s Prospex “Digi Tunas,” ref. SBEP001, SBEP003, SBEP005, SBEP007, and SBEP009

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Some watches are just right as digitals. By “right,” I mean that they just look as though they were always intended to have moving numbers rather than moving hands. There’s a good chance of getting burned at the horological stake for saying it, but the Seiko Tuna has always been one of them. Before you rush for the matches and the watch oil, a digital Tuna isn’t completely without precedent. After all, the H558-5009 “Arnie” in the early 1980s featured a small digital display.

And why not? Digitals are clear, reliable, robust, and good under both pressure and temperature variation. Diving watches need to be all those things and the Tuna, after all, is the arch-diver. And sure, a diving watch is a bit academic in these days of diving computers, but there are plenty of enthusiasts who still want a watch to go alongside their dive tech.

From left to right: SBEP001, 003, and 005

Looks like Seiko Japan have reached the same conclusion with the launch of the Prospex SBEP range. These are fully digital Tunas (you have no idea how hard it is to resist making some sort of bad pun about “fish fingers” at this point). Using Seiko’s typically snappy and memorable numbering system, the standard models have been christened SBEP001, SBEP003 and SBEP005. The SBEP007 model (so, Mr Bond, we meet again…) is limited to 600 units sold through Journal Standard shops, and there will be just 300 SBEP009s in Urban Research shops in Japan.

What does the range look like? The 001 has the standard black shroud case with silver pushers. The 003 features a neat nod to past glories with a Pepsi bezel, whereas the 005 blings it up with gold pushers. The 007 comes (of course) on a rugged nylon mil-strap (if only it had been the Bond pattern) with stainless pushers and screws, and the 009 is just black—plain black. If you’re a Hitchhikers’ Guide to Galaxy fan you may be reminded of Hotblack Desiato’s spaceship as described by Ford Perfect, “It’s so . . . black! You can hardly make out its shape . . . light just seems to fall into it!” If you’re a Tuna fan, you’re probably thinking more along the lines of a “Digi Darth.”

Left to right: SBEP007 and 009.

Yuki Kajiwara, creative director of LOWERCASE, is the man behind the design. It’s not his first excursion for Seiko, with the SBDN028 and the SBDL045 Prospex limited editions to his name. He’s certainly a brave designer. Taking on an analog icon like the Tuna and digitizing it must have been quite a brief.

For any Tuna to work as a design, form must follow function. The Tuna is a watch designed to do a job, not slip under a cuff and look nice over cocktails. There’s no room on a watch like this for fripperies. And Kajiwara succeeds. It looks like the large negative display manages to balance legibility with discretion. The decent sized pushers—whether gold, silver or black—are textured, so your thumb won’t slip (they’re on the left side of the case). Bet you just moved your hand to make sure that worked!

The outer double case is a black, ion-plated titanium protector, so it should take a good amount of punishment without scratch or protest. It’ll shrug off salt water corrosion, too. According to Seiko, it has no fewer than 20 patents behind it. And you get a proper 200 meters of water resistance.

Compared with the 1,000-meter depth rating of the SBBN021, it would be easy to think of these new watches as shallow-water takes, but that would be wrong. Most divers seldom go deeper than 40 meters and the deepest ever scuba record stands at just over 332 METERS—and the guy who set that is an ex-Egyptian army special forces officer who’s been a diving instructor for the last 17 years. So, in the real world, if you want a watch that’ll stand a bit of splashing in the hotel pool and any real-world level of snorkeling or scubaing, the “Digi Tuna” will hack it.

These watches won’t need much babying. There’s no need to change batteries as the cal. S802 movement is fully solar powered. Fully charged, you’ll have enough power to spend the summer diving, surfing, or just drinking cocktails and pretending. Then you can put your watch in a drawer and forget about it until next season. And if you really do forget about it, there are still another 15 months of standby power, all of which you can monitor from the power indicator at the bottom of the screen. It’s a proper “sling it on and forget it” watch.Which brings us to the inevitable comparisons with G-Shock range. Solar power, chrono, world time, robust construction and a 200-meter water resistance are all well-known G territory. The SBEPs are pitched pretty firmly towards the upper middle of the G range, against watches like the G-9300. but well below the MR-G megabuck models. But the Seiko is a great deal less fussy in the way it operates and displays its functions. And its ruggedness has a simplicity that the Gs sometimes lack. Interestingly, the case backs of the Seikos are remarkably similar to those of cheaper G-Shocks, held on with four securing screws in the tab corners of the case.


The SBEP is not a shy and retiring watch. This one is 49.5 millimeters in diameter and 14 millimeters thick. You’ll not forget you’ve got it on. But the dimensions mean you shouldn’t have too many problems reading the time at a glance.

But what about a rotating bezel on a digital watch? What’s the point? In fact, the SBEP has an outer, one-hour minutes track that makes sense of the bezel. You can track your elapsed time against it. And there’s a bit of Seiko humour going on too with the trademark Pepsi bezel variant.There’s some humor behind the brochure and web photos too. Notice that the time is always 10:08 for a Seiko digital? Why on earth choose such a random number?  Quite simply because that’s the position of the hands in publicity shots for analog watches.

The display should be decently visible at night too. Tap the glass and you get a backlight to help give you the time. And it doesn’t matter where you are. There’s a dual time for 44 cities around the world and you can measure your flight delays to 1/10 of a second with the chronograph. There’s a timer too, and the calendar will set itself until December 31, 2067.

The cost is pretty good for a digi beater. You’ll pay around $255 at today’s exchange rate (¥28,000) for the SBEP001, with the 3, 5, 7 and 9 coming in a shade more at $274 (¥30,000). That looks like pretty good value for a robust, take-anything watch. Seiko Japan

Mark developed a passion for watches at a young age. At 9, he was gifted an Omega Time Computer manual from a local watch maker and he finagled Rolex brochures from a local dealer. Today, residing in the Oxfordshire village of Bampton, Mark brings his technical expertise and robust watch knowledge to worn&wound.
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