Monochrome Watches
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The New, Compact SPB313, SPB315 & SPB317 Are Seiko Prospex’s Thinnest Dive Watches (Live Pics & Price)

A compact and thin cushion-shaped case making for a vintagey & highly wearable dive watch.

| By Brice Goulard | 4 min read |
Seiko Prospex Automatic Diver 200m SPB313J1 SPB315J1 SPB317J1

If Seiko‘s expertise in dive watches isn’t to be demonstrated anymore, there are a few comments that can be made about many of the older models released by the Japanese manufacturer, and that has mostly to do with the actual size of the cases. If you take for instance the most classic models, such as the Turtle and Samurai, or the King Turtle and King Samurai, we’re talking about 44mm or more. These are well-shaped, sure, but far from compact. Recently, however, the brand decided to go smaller, with compact 62MAS-inspired or 1968 Reinterpretation watches. And the trend continues with the new Seiko Prospex Automatic Diver 200m SPB313J1, SPB315J1 & SPB317J1, the thinnest dive watches in the range. 

Seiko’s history is packed with important watches, such as the 1965 62MAS (the brand’s first dive watch), the 1968 Hi-Beat Automatic Diver 300m and the 1970 Turtle watch. Seiko has long used these historical models to create modern watches reissuing vintage design cues. What we’re looking at today, with the new SPB313J1, SPB315J1 and SPB317J1, is again part of these models, with a design that feels rather retro-inspired, for a good reason. This model takes inspiration from a 1968 watch, the rather confidential 6105-8000 Automatic Diver, successor to the legendary 62MAS.

Seiko Prospex Automatic Diver 200m SPB317J1

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These new Seiko Prospex Automatic Diver 200m are mostly noticeable for their design and, importantly, their proportions. As said in the introduction, Seiko has decided for a couple of years now to downsize many of its dive watches, giving them far more wearable proportions and thus better ergonomics for daily use. An oversized watch can make sense for a professional diver when worn over a wetsuit… not so much with a linen shirt during a weekend. And since most of these watches will be worn on a daily basis or for leisure activities, reducing them is certainly a wise decision – at least, one we totally approve, here at MONOCHROME.

Seiko Prospex Automatic Diver 200m SPB315J1

Back to the watches. All three models in this new range share the same specifications and case. As such, we’re talking about a late-1960s kind of case, with a cushion shape, straight and sharp casebands, and circular brushed surfaces on top. In typical Seiko style, the crown is positioned at 4 o’clock. And regarding the dimensions, these new SPB313J1, SPB315J1 and SPB317J1 measure 41mm in diameter, with a compact lug-to-lug measurement just below 47mm. And the best is the thickness, as these are the thinnest Prospex models, with 12.3mm in height. And on the wrist, it wears just perfectly. Nice balance between compactness and presence, without compromising the specifications.

Seiko Prospex Automatic Diver 200m SPB317J1

The rest of the case feels classic, with a screw-down crown and a solid steel screwed caseback, both guaranteeing a comfortable 200-metre water-resistance. The top of the watch is protected by a sapphire crystal with internal anti-reflective coating and is framed by a unidirectional rotating bezel. The latter rotates on 120-clicks and features an aluminium insert, entirely graduated with a 60-minute scale.

Seiko Prospex Automatic Diver 200m SPB313J1

As for the dial, no surprises, with a design that is shared with multiple other watches from the Prospex range, including the signature combination of applied markers and oversized luminous hands. In this version, the brand has opted for the retro “shovel” shaped hand with luminous and red tip and, in order to comply with the latest requirements of ISO standards, the date is placed at 4:30 so all markers can be luminous.

Seiko Prospex Automatic Diver 200m SPB317J1

This new range of Prospex Automatic Diver is available in 3 different editions. First, there’s the highly classic SPB317J1, which features a grained matte black dial with silver-coloured accents on the dial and the bezel. This version is worn on a black, textured silicone strap. Next in line is the SPB313J1, with a matte white dial and dark-coated hands and markers. The bezel’s insert is black with a silver scale. Finally, there’s the SPB315J1, with a gilt-inspired colour scheme. The dial has a smooth texture and a very dark grey colour, while the markers, hands and diving scale are gold-coloured for a cool vintage touch. These two editions are worn on a flexible 5-link brushed steel bracelet with a folding clasp, push-buttons and diving extension.

Seiko Prospex Automatic Diver 200m SPB315J1

Inside these compact cases is a well-known movement, the in-house calibre 6R35. Running at 3Hz and part of the brand’s mid-range portfolio of movement, it is mostly interesting due to its extended power reserve of 70 hours. The movement is hidden behind a closed caseback and, even though not mentioned to us, has a claimed accuracy of -15/+25 seconds per day – which we know to be a rather safe estimation.

Seiko Prospex Automatic Diver 200m SPB317J1

The Seiko Prospex Automatic Diver 200m SPB313J1, SPB315J1 and SPB317J1 will soon be available from the brand’s boutiques and retailers, and are released as part of the permanent collection. Prices are EUR 950 for the SPB317J1 and EUR 1,150 for the SPB313J1 and SPB315J1. For more details, please visit

10 responses

  1. Hi Brice, thanks for this , do you know if the bracelet has got some kind of micro-adjustment on its clasp ?
    Kudos to Seiko for making « wearable » watches again 🙂

  2. @Pierre – thanks for your kind words. There’s no micro-adjustment on the clasp, however, it retains the diving extension to enlarge the bracelet when wearing it over a wetsuit.

  3. They all seem quite nice and at last have sapphire. The trick will be convincing people to pay those prices when they remember what similar pieces cost just a few years ago and when microbrands are offering more, in some cases an SW200 for about half the price.

  4. Super happy to see those. I am confused about where they are made. Do you know if they are made in Japan? There is a J in the model number, but it only says «Japan» on the dial. Usually Seiko makes it clear by writing «made in Japan» or «mov’t Japan».

  5. Just beautiful. I think SPB317 will replace SPB147 as my favourite “affordable” Seiko diver.

    This is a strap watch, but that bracelet looks really expensive for a Seiko—are those end links constructed of multiple pieces?

  6. Accuracy, price, bezel alignment. All three need to be better for this kind of money.

  7. I have received my SPB313 and can answer a couple of the questions above. Firstly, the clasp has a two-position microadjust (spring bar type). The bezel diameter (including the coin edge) is 39mm.

    A couple of further comments: on mine the bezel pip is not off centre. The watches pictured here are clearly pre-production prototypes so it may be something that has been fixed before production – or I might just be lucky.

    Last thing – the markers on these are not applied. They are done the same way nearly all Prospex divers are done – even the high end models like the SLA017. The markers are raised by stamping the dial, and then machined flat to make them shiny before being filled with lume. Seiko’s reasoning for this is the same reason they also do not have applied logos or anything else – they don’t want any risk of anything falling off the dial if the watch receives a hard knock. Whether you want to take that at face value is up to you.

    Overall – I think these are good watches. I think they do enough to justify their pricing and it shouldn’t be hard to find a discount (as I did). I’d honestly rather have one of these than a Doxa.


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