Seiko SPB317 Review: A Slimmed-Down Heritage Diver Under $1,000

Introduction

Seiko holds a special place in the history of dive watches. While the Japanese brand arrived later than some of its Swiss peers, its legendary lineup including the 62 MAS, the Willard, the Turtle, and the SKX has earned it a seat at the table among diving brand legends. In the modern lineup, Seiko offers an entire spectrum of dive watches, from prospect models under $500 to reinterpretations of the 62 MAS and Marine Masters that climb into the thousands.

The Seiko SPB317 sits in a rare pocket within that spectrum. Falling under $1,000 and accommodating a variety of wrist sizes with its case diameter, it stands as one of the most compelling dive watches in that price range. Released in 2022, the SPB317 serves as a modern iteration of the 6105-8000 series, a lesser-talked-about release from the late 1960s that bridged the gap between Seiko’s earliest purpose-built divers and later models like the Willard and the Turtle.

Who This Watch Is For

The SPB317 is for watch enthusiasts who appreciate traditional Seiko case forms and want maximum value for their money. It carries the heritage of the 6105-8000, which pioneered the case silhouette many have come to expect from Seiko, including the 4 o’clock crown position. With the discontinuation of models like the Willard and the SPB143, the 317 has become increasingly compelling as one of the few remaining options in its price bracket.

This watch suits collectors and daily wearers who want a professional-grade dive watch with historical significance without stepping into the four-figure price range. It also appeals to those with smaller wrists who have struggled to find a Seiko diver that wears comfortably. The 317 delivers a slimmed-down take on the classic cushion case design, making it accessible to a wider range of wrist sizes than its larger siblings.

Case and Wearability

The case of the SPB317 explains where its nicknames come from. Often labeled the slim turtle or the slim Willard, it is neither a perfect representation of either line, given that the 6105-8000 predates the originals of both. The nickname does accurately convey the concept of being a slimmed-down version of both designs.

Despite its 41 mm case diameter, the SPB317 wears smaller than the numbers might imply. The case height locks in at 12.3 mm, and the lug-to-lug measures 46.5 mm, making it small wrist-friendly. Factoring in these considerations, the 317 wears close to a 39 mm case equivalent. It is reasonably thin for Seiko dive standards while upholding ISO 6425 compliance and maintaining a water resistance of 200 m.

The finishing is tool watch correct, with circular brushing on the anterior sides and horizontal brushing on the flanks. The inclusion of drilled lugs makes strap swapping opportunities plentiful, especially thanks to the 20 mm lug width. Seiko’s super hard coating on the stainless steel improves scratch resistance, reportedly offering two to three times the resistance of standard untreated stainless steel. The sapphire crystal features a gentle curve and anti-reflective coating on the underside.

Dial and Details

The dial continues the historic Seiko diver vibe with a mission-specific matte black finish that almost appears charcoal in different lighting conditions. Applied indices follow the form of vintage models with lume-filled rectangles marking the hours, set just inward of the printed white minute track. A pair of trapezoids at 12 join together to form a shield-like body, a tribute to the original 6105-8000.

The hands get a more modern shape recalling the broader style of certain Marine Masters. A beautiful detail is the mixed finish on these hands, with one side brushed and the other polished, and a central facet drawing a line of separation that provides contrast when viewed straight on. The second hand offers a nod to the past with its stoplight tip accented in red.

The lume in the hands and indices uses Seiko LumiBrite, which is some of the best in the industry. Seiko licensed and updated the Swiss Super-LumiNova formula with europium and dysprosium, claiming it absorbs light faster and glows longer after being activated. The date window is discreetly tucked away at 4:30 behind a diminutive circular window color matched to the black dial, a placement that may win over many on both sides of the date window debate.

Movement and Performance

Inside the SPB317 beats the automatic 6R35 caliber, first introduced in 2019 as an upgrade to the 6R15. The movement runs at 3 Hz or 21,600 vibrations per hour, has 24 jewels, and offers both hacking and hand winding. It features Diashock protection, an Etachron regulator, bidirectional winding courtesy of Seiko’s magic lever, and magnetic resistance of 4,800 amperes per meter or 60 Gauss, making it ISO 764 compliant.

Seiko declares the accuracy as minus 15 to plus 25 seconds per day, which is probably the number one attribute working against this watch for those who value utmost precision. These numbers tend to be very conservative, and in testing across five different positions, this version did not run faster than eight seconds a day at any position, with the majority of positions running within five seconds a day of accuracy. Performance will vary from model to model.

The finishing on the 6R35 is industrial and somewhat bare-bones, with machine striping on the signed rotor and not much beyond that. This is a non-issue since the watch sticks to the classic Seiko diver script with a solid screwed-in case back featuring an embossed tsunami wave design surrounded by a checklist of pertinent specs. Seiko is one of watchmaking’s most vertically integrated manufacturers regardless of price, so the movement can confidently be called in-house.

Buying Advice

The SPB317 delivers appeal that larger models like the Sumo do not. However, if you are looking for more conventional looks in a dive watch, this may not be the right choice. The case silhouette is not designed for mass market appeal, and the 62 MAS case types will probably sit better with those seeking a more traditional aesthetic.

On the other hand, if maximizing your dollar while upholding traditional Seiko case forms is more your thing, the SPB317 is probably the most compelling package for a diver from the brand under $1,000 today. There is some uncertainty about how long this watch will continue in its current form, as Seiko has been phasing out many of its best-selling watches utilizing the 6R35, including the SPB121, the Willard, and the SPB143. The 317 sits in a nice middle ground with its unimpeachable looks, slimmed-down case, and a price tag that does not include a comma.

Conclusion

The Seiko SPB317 is a compelling package when you factor in wearability, price, and the history that goes along with it. It occupies a strange and valuable pocket in Seiko’s dive watch lineup, offering professional specs, heritage design cues, and a comfortable fit at a price point that remains accessible. For those who appreciate traditional Seiko case forms and want a dive watch that honors the brand’s legacy without breaking the bank, the SPB317 is a watch worth serious consideration.