The 2025 Seiko Prospex Speedtimer Datsun 240Z (SPB517) combines a high-quality self-winding movement with a carefully calculated vintage-style exterior. It is also a tribute to a car that changed everything.
✓ Pros: The high-grade caliber sourced directly from their Grand Seiko brand. The dial offers superb legibility. The recommended street price of $1150.
❌ Cons: It feels like they a little overdid it with the Datsun logo.
Seiko Prospex Speedtimer Datsun: The Overall Impressions
Have you checked a price of a luxury watch recently? It hurts, right? A Speedmaster costs almost $8000. An Oris three-hander is about $2500. A Longines Spirit Pilot will be close to $3500 after taxes.
In this economy©, a good watch is rapidly becoming a luxury in the literal meaning of the word. Brands don’t need copywriters to convince people that their watches are exclusive. The price tags make them exclusive.
In this respect, this limited-edition Speedtimer is a bargain. For just over $1100, Seiko will sell you a watch that combines great build quality, an almost perfectly executed exterior, and a solid automatic movement.
Yes, it’s a niche model and its versatility is somewhat limited. Still, this is one of the best options for a sporty “entry-luxury” timekeeper that one can find today.
The Compact Case
Seiko Prospex Speedtimer Datsun 240Z arrived in a compact and elegant hard-coated stainless-steel case. It looks like its main source of inspiration was the vintage Grand Seiko 6145-8000 three-hander. It’s forgotten now, but it became a hit the moment Seiko introduced it in the 1960s.
Of course, it isn’t a “re-issue”. It’s not even an homage. It’s better than that.
Compared to the modest 36.5 x 42.00 (lug-to-lug) x 12.00 millimeters of the original, this one is noticeably larger at 39.5 x 44.5 x 12mm. As a pleasant side effect, the watch looks slimmer because of the better proportions.
Of course, the increase in size has nothing to do with the inner workings of the watch.
The relatively new Seiko caliber 6R55 is even smaller and thinner than the Caliber 6145A that powered that vintage Grand Seiko. It’s pure marketing: people just don’t buy small watches anymore.
The body is also more streamlined (some may call it “simplified”.) The front part where it meets the bezel ring is completely flat, for example.
Wrapping up this section, the extra crown at 4 o’clock is one of those rare moments where form follows function.
Unlike the one on the Oris BC4 Flight Timer, it’s not here to impress you with an unusual design. It’s here to chew gum and operate the beautiful 15-minute timer on the inner bezel.
The Leather Strap
The black leather strap doesn’t look particularly expensive (it’s not a particularly expensive watch either.) Yet it looks cool and it also sports a nice three-fold stainless steel clasp with push button release.
They also glued the black perforated leather to a bright red base and accented it with light-grey thread that plays nicely with the brushed steel lugs.
The red leather not only makes the strap look a bit more premium. It also protects the stitches from water and sweat. It also makes it way easier to clean the strap from all the gunk that accumulates during the summer.
As usual for Seiko, the stitching is impeccable, but you can always swap this strap for an even more premium feel. With the lug width of 20mm, there are metric tons of options out there.
The Mechanism: Seiko caliber 6R55
First introduced in early 2023, the Seiko caliber 6R55 originally powered their more expensive King Seiko collection.
By today’s standards, it’s a relatively slow movement with its cadence of balance of just 21,600 vibrations per hour. Yet it’s definitely not archaic, at least when it comes to all the modern alloys and advanced manufacturing processes involved in making of these calibers.
The main selling point here is the guaranteed power reserve of 72 hours. It doesn’t sound particularly impressive, but I remember how 15 years ago it was reserved for very exclusive watches made by Panerai or A. Lange & Sohne. Now you can have it in a Seiko.
Compared to most current ETA calibers that barely make it past 44 hours (their Powermatic 80 is sort of an exception here,) this is a lot of hours for a mass-produced entry-luxury timekeeper.
But Is It Reliable and Accurate?
Dude… Even though the 6rxx family seems to be here forever, the 6R55 is still a relatively new caliber. There’s just not enough data to make claims about its long-term reliability and accuracy.
Still, a quick (about two hours, I tend to get hyper-focused) scan through several forums, shows that most owners of 6R55-powered watches are happy with the way they keep time. The daily deviation seems way lower than the official accuracy of -15/+25 seconds per day.
As they say, better materials equal better quality. Some Swiss manufacturers that equip their movements with plastic parts to cut costs should take a note. Or they can continue with their efforts at increasing “shareholder value” at the expense of their customers. I don’t care; it’s their own funeral.
The Dial
The New Look
Compared to the base model, all the modifications to the dial are purely cosmetic.
(Images courtesy of Seiko.com)
The limited-edition version is now matte-black while the dark-orange accents are of a darker shade of red. The black central seconds hand with its orange tip is now also of the same red color as the Datsun 240Z that inspired this tribute.
Same with the 15-minute scale on the inner bezel.
The scale is the most interesting part of the dial: it’s not just a color accent, but an actual moving part. It stays around 9 and 12 o’clock by default but you can move it around the chapter ring using the second crown. This is probably one of the most elegant replacements for the ubiquitous rotating bezels that I am kind of tired of.
For some unobvious reason, the scale is now mirrored by another scale on the other side of the bezel. I mean, it looks sort of entertaining, but it also adds an unnecessary distraction to the overall flawless display of time.
The rest is trivial.
The signature X of the Prospex series moved from its usual position in the lower part of the dial to the upper side.
The “Automatic 3 Days” and the “20 BAR” inscriptions are simply gone: there’s now a Datsun logo there. The Datsun Edition also replaces the original typeface on the minute track with something looking like a “[Generic Font] Narrow Bold.”
Hm, what else? Oh, the beige LumiBrite replaced the white one of the original making it feel even more vintage.
That Datsun Logo Though…
Speaking of the logo, I can’t say that I am particularly happy about it.
On the one hand, it does a good job as a counterbalance to all the branding on the upper half of the dial. On the other, it is too bright, too colorful, and too big for an otherwise very reserved watch. It’s an eyesore.
I don’t say that it’s a design error: Seiko’s designers obviously know what they are doing. I just wish Seiko followed Tag Heuer’s example at how they display the “Gulf” logo in their Monaco Gulf chronographs: a tiny picture that is almost invisible on the big dial: it’s just there (somewhere.)
The Superb Legibility
Even though there’s nothing groundbreaking about Speedtimer’s dial layout, it isn’t necessarily a bad thing.
The indicators look familiar; you don’t have to guess how they work and what they point at.
There are healthy chunks of LumiBrite on the meticulously executed hour and minute hands that emit bright green glow in darkness.
The luminous dots on the massive hour markers, as well as the index triangle on the bezel scale, are also big enough to be easily seen at night.
As usual, the only potential readability issue here is the microscopic circular calendar aperture between 4 and 5 o’clock of the already relatively small dial.
The Pricing & Availability
The watch hit American stores in September 2025 at an MSRP of $1150. That’s a lot of watch for the price.
Considering Seiko’s traditional zero-tolerance approach to quality control and their engineering expertise, this watch can easily compete with twice more expensive automatic three-handers made by Tudor or Tag Heuer in terms of value for money and overall perceived quality.
See also: Grand Seiko Spring Drive GMT Edition is JDM-exclusive
Photos: Seiko
WWR’s Final Verdict
Looking less dressy than the source of its inspiration, the watch is also more versatile. You can wear it with blue jeans and a plain T-shirt, or you can wear it with a suit: it will look great either way.
With its current MSRP of $1150 before taxes, it is also quite affordable considering the reputation of the movement and the overall build quality.
Originality 4/5
Versatility: 5/5
Build Quality: 5/5
Usability: 4.5/5 (mostly because of the second crown)
Overall Legibility: 4.5/5
Nighttime Legibility: 5/5
Value for Money: 5/5
Overall Rating: 4.5/5
Seiko Prospex Speedtimer Datsun 240Z (SPB517) specification
Price (MSRP): $1150 at the time of publishing this review
Winding: Automatic
Movement: Caliber 6R55 with hacking seconds, Made in Japan
Number of Jewels: 24
Cadence of Balance: 21,600 vph
Power Reserve: 72 hours
Functions: Hours, minutes, seconds, date, 15-minute timer
Case & Crown: Stainless steel
Bezel shape: Round
Size: 39.50 mm
Case height: 12.00 mm
Lug-to-lug: 44.5mm
Lug width: 20.00 mm
Front crystal: Sapphire, curved, anti-reflective on the inside
Back: Solid, engraved
Dial: Black
Hour markers: Luminous, applied
Hands: Luminous (LumiBrite)
Water resistance: 200 meters
Strap: Black perforated Cow leather; Three-fold steel clasp with push button release