Seiko Dive Watches – History & Information

A hugely popular watch range amongst recreational and professional divers offering excellent value for money and high standards of Japanese quality assurance. My personal favourite is the Seiko SLA017 – a modern day re-interpretation of the 1965 classic and original Seiko dive watch. This page is focused on providing information and a little background history on these iconic watches.

Note – all images courtesy of Seiko Watches (1)

A Seiko SLA017 – a modern interpretation of the 6217 (62MAS-010) 1965 dive watch

Seiko Prospex dive watch range

Seiko’s current range of Prospex diver’s watches is huge – around 30 models in all. It covers budgets from approx £300 to well over £5,000. The Seiko Prospex dive watch range represent the pinnacle of horological build quality and innovation. The name itself stands for “Professional Specification”. In the Japanese market (and growing worldwide) Seiko’s premium label watches hold similar status to TAG Heuer, Rolex and Omega.


Seiko Dive Watches for sale

If you are interested in buying a watch – please start here with all the Seiko Dive watches listed for sale this week.


Quick links – information & history

or just scroll down for a trip down the Seiko Dive Watch memory lane ….

Seiko 6217 | Seiko 6105 | Seiko 6306 | Seiko 6309 | Seiko 7002 | Seiko SKX

Seiko Tuna | Seiko Turtle | Seiko SKX009 | Seiko SKX007 | Seiko Samurai


A short history of the Seiko Dive Watch

This very short summary of the history of the world’s most popular diver’s watch has been compiled from various reliable online sources and trusted references. There is one source that needs a special mention and that is Kevin Chan (2). The timeline below highlights each generation of Seiko dive watch with years of manufacturer, important notes and some popular model numbers (eight digits eg 7S26-5678).

NOTE – please click the model number links to find EXACT match watches listed for sale recently.

1st Generation – Seiko 6217 Dive Watch

Model reference 6217 – Years in production: 1965 to 1968. Water Resistant: 150m. Black bezel only. Movement: Calibre 6217 automatic movement with 17 jewels running at 18,000bph. The 6217 movement is non-hacking and cannot be hand wound. This model is often referred to as the Seiko 62MAS-010. 62 from the Calibre 6217 and MAS from Model Automatic Selfdater

A vintage Seiko 6217-8000 – courtesy of eBay seller niko-o-onlineshop
  • 6217-8000 – black dial – non-clicking, bi-directional black bezel. Signed “Japan” between 6 and 7 o’clock.
  • 6217-8001 – black dial – non-clicking, bi-directional black bezel. Signed “Japan” between 6 and 7 o’clock. As 8000 version but a larger / improved crown design

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2nd Generation – Seiko 6105 Dive Watch

Model reference 6105 – Years in production: 1968 to 1977. Water Resistant: 150m. Black bezel only. Movement: Calibre 6105 automatic movement with 17 jewels running at 21,600bph. There are two versions of 6105 – the 6105A, non-hacking (second hand does NOT stop when crown pulled out) and the 6105B with hacking for precise setting of the second hand. Neither movement can be hand wound.

A vintage Seiko 6105-8000 – courtesy of eBay seller Sillimtao

MKI

  • 6105-8000 – black dial – non-clicking, bi-directional black bezel. Features the calibre 6105A in a symmetrical cushion case. Signed “Japan” between 6 and 7 o’clock. Dial states “Water 150m Proof
  • 6105-8009 – black dial – non-clicking, bi-directional black bezel. Features the calibre 6105A in a symmetrical cushion case. Signed “Japan” between 6 and 7 o’clock. Dial states “Water 150m Proof

MKII

  • 6105-8110 – black dial – non-clicking, bi-directional black bezel. Features the calibre 6105B in an asymetrical case. Signed “Japan” between 6 and 7 o’clock. Dial states “Water 150m Resist
  • 6105-8119 – black dial – non-clicking, bi-directional black bezel. Features the calibre 6105B in an asymetrical case. Signed “Japan” between 6 and 7 o’clock. Dial states “Water 150m Resist

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3rd Generation – Seiko 6309 (& 6306) Diver’s Watch

Seiko 6306 (the ORIGINAL Seiko Turtle)

Model reference 6306 (Japanese market) – Years in production: 1976 to 1981. Water Resistant: 150m. Black bezel only. Movement: Calibre 6306 automatic movement with 21 jewels running at 21,000bph. This 6306 movement is hackable (stop second hand by pulling crown out) but cannot be hand wound. This is the first time the “Turtle” case design makes an appearance. All models show “WATER150mRESIST” on the dial

A vintage Seiko 6306-7000 – photo courtesy of eBay seller YS-variety
  • 6306-7000 (original Turtle) – black dial, 60 click, bi-directional black bezel. “Japan 6306” on dial between 6 and 7 o’clock.
  • 6306-7001 (orignal Turtle) -black dial, 60 click, bi-directional black bezel. “Japan 6306” on dial between 6 and 7 o’clock.

Seiko 6309 (the Turtle has landed)

Model reference 6309 (mainly International market) – Years in production: 1976 to 1988. Water Resistant: 150m. Black bezel only. Movement: Calibre 6309 automatic movement with 17 jewels running at 21,600bph. This 6309 movement is non-hacking and cannot be hand wound. All models show “WATER150mRESIST” on the dial. Seiko Turtle is a collective term that covers all the 6306 and 6309 Seiko dive watches with the cushion shaped case.

MKI

  • 6309-7040 – Intended for the Japanese market. Black dial, 60 click, bi-directional black bezel’ “Japan 6306” on dial between 6 and 7 o’clock
  • 6309-7049 – Intended for international market. Black dial, 60 click, bi-directional black bezel’ “Japan 6306” on dial between 6 and 7 o’clock

MKII

Featuring a slimmed down case – similar to that used later in the 7002 and SKX lines. Some people refer to this case style as the “slim Turtle”. All 150m ISO rated water resistancy

  • 6309-7290 – black bezel  international model with no mention of jewel count
  • 6309-7290 – black bezel Japanese model with “17 jewels” under the WATER200mRESIST and “made in Japan” between 7 and 6 o’clock
  • 6309-729A – Pepsi bezel –  international model with no mention of jewel count
  • 6309-729A – Pepsi bezel –  Japanese model with “17 jewels” under the WATER200mRESIST and “made in Japan” between 7 and 6 o’clock

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4th Generation – Seiko 7002 Dive Watch

Model reference 7002 – Years in production: 1988 to 1996. Water Resistant: 150m & 200m. Black bezel & Pepsi bezel (red & blue). Movement: Calibre 7002 automatic movement with 17 jewels running at 21,600bph. The MKI versions of 7002 featured the most common 60 click bi-directional bezels. The MKII models introduced a 120 click uni-directional bezel, as found on the later Seiko SKX 7S26 models.

A vintage Seiko 7002-7000 dive watch – courtesy of eBay seller Legend of Sellda

MKI 7002 were ISO rated to 150m

  • 7002-7000  150m International version – not made in Japan – no jewel count on dial (17J) – BLACK bezel
  • 7002-7009 150m USA version – also not made in Japan – no jewel count on dial (17j) – BLACK bezel
  • 7002-7001 Japanese market version – 150m and 17 Jewels on dial and Made in Japan along bottom between 7:30 and 6 o’clock BLACK bezel
  • 7002-700A – international version – no jewel count on dial (17j) – PEPSI bezel
  • 7002-700J – Japanese market version – 150m and 17 Jewels on dial and Made in Japan along bottom between 7:30 and 6 o’clock PEPSI bezel

MKII of 7002 were ISO rated to 200m

There was also a move from a 60 click bi-directional to 120 click unidirectional bezel. Wording on dial changed from WATER150mRESIST to DIVER’s 200m

  • 7002-7039 200m International version – no jewel count – BLACK and PEPSI bezel
  • 7002-7020 this later model featured a radical change in bezel design.

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5th Generation – the SKX range of Seiko Divers Watch

Model reference 7S26 – Years in production: 1996 to 2019. Water Resistant: 200m. Black bezel & Pepsi bezel(red & blue). Movement: Calibre 7S26 automatic movement with 21 jewels running at 21,600bph. All the SKX range feature UNI-DIRECTIONAL 120 click bezels. Most popular by a long way in this range is the Seiko SKX009 (Pepsi) and Seiko SKX007 – click links for more information.

A Seiko SKX007 7S26-002X – courtesy of eBay seller defaultguy01

Seiko 7S26-0020

  • SKX007 K1 – black bezel, international market, NOT made in Japan
  • SKX007 J1 – black bezel, Japanese market “Made in Japan” between 7 o’clock and 6 o’clock
  • SKX009 K1 – Pepsi (red & blue) bezel, international market, NOT made in Japan
  • SKX009 J1 – Pepsi bezel, Japanese market “Made in Japan” between 7 o’clock and 6 o’clock
An example of a Seiko SKX009 200m diver’s watch – courtesy of eBay seller WatchNationShopLtd

Other popular models in 7S26 range

  • SKX781 (7S26-0350, Seiko Monster with black dial)
  • SKX779 (7S26-0350, Seiko Monster with Orange dial)
  • SKX011J (7S26-0020, as per the SKX007J with orange dial and gold letters)
  • SKX013 & SKX015 (7S26-0030 mid-sized 38mm – 200m diver – black bezel & blue-and-red bezel)
  • SKX023 & SKX025 (7S26-0050 a mid-sized 38mm 100m diver – black & blue-and-red bezel. Sometimes referred to as the “Seiko Submariner” due to it’s similarity to the Rolex Submariner)
  • SKX031 & SKX033 (7S26-0040 a mid-sized 39mm 100m diver – black & blue-and-red bezel. As above – sometimes referred to as the “Seiko Submariner”)

Seiko Watch Movements

Automatic

A Seiko automatic watch relies on movement of the wrist to keep it ticking. Simply put, every time your wrist moves a semi-circular rotor spins – in effect – winding the watch’s mainspring. The movement does not have to be forced, it works from natural gestures expressed throughout the day. Most Seiko watches also allow for “hacking” – the manual winding of the watch to give it a headstart.

A closeup photo of the Seiko 7S26A automatic movemement found in many Seiko Prospex dive watches
A popular Seiko 7S26 Automatic movement

If the watch hasn’t been moved for a day or two it will stop running. To restart the watch simply wave it back and forth for a minute of two, or, if it features the hacking feature, unscrew the crown and give it 10 to 20 winds (back and forth)

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Accuracy of an Automatic watch

Seiko produce several automatic movements. In horology a watch’s movement is often referred to as a CALIBRE. From the current range a majority of dive watches will be built around one of the following calibres

Popular Seiko Automatic Calibres

  • 4R35
    • 4 beats per second | 23 jewels | 41 hours | +45 to -35 secs/day
  • 6R15
    • 6 beats per second | 23 jewels | 50 hours | +25 to -15 secs/day
  • 7S26
    • 6 beats per second | 23 jewels | 40 hours | +40 to -20 secs/day
  • 8L35
    • 8 beats per second | 26 jewels | 50 hours | +15 to -10 secs/day
  • 8L55
    • 10 beats per second | 26 jewels | 55 hours | +15 to -10 secs/day
  • 6R15
    • 6 beats per second | 23 jewels | 50 hours | +25 to -15 secs/day

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Solar

Solar power was a groundbreaking technology introduced in to Seiko watches in 1977. When fully charged a Seiko solar powered dive watch should give 10 months accurate time keeping.

The time keeping is managed by a quartz crystal. However – this crystal is powered by a rechargable battery – charged by light. This makes the solar watch as accurate as most regular battery powered quartz. The Seiko V157 should provide an accuracy of +/-15 sec/month

Note – a solar powered watch does NOT rely solely on sunlight. Light from electric light bulbs and other light sources will also charge the battery

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Kinetic

Whereas a solar powered watch charges the battery from energy stored within light – a Kinetic watch charges the battery from kinetic energy. It’s basically a combination of an automatic watch and a quartz watch. Kinetic energy is the energy an item possesses due to its’ motion. Motion from the wearer of the watch causes the semi-circular rotor to turn a miniature electrical generator that subsequently charges the battery.

The Seiko Kinetic movement showing rotor, battery and coil
A Seiko Kinetic movement with rotor, battery and coil

In effect, the watch has turned kinetic energy in to electrical energy – think like a dynamo on a bike – pedalling spins the dynamo which in turn charges the batteries which in turn power the light.


Quartz

From the current product line-up (2019) there are only a couple of dive watches with a quartz movement. The Limited Edition S23626J1 (with a price tag over £2k) comes equipped with a Seiko Quartz 7C46 movement. This unit will provide an accuracy of +/- 15 sec/month with an approximate battery life of 5 years.

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My own current dive watches - the Citizen Eco-Drive, a Belmont Supermarine S500 and a Seiko Kinetic Divers 200m

My current Seiko is a SKA761P1 (on the right) – one of just 3 x Seiko Kinetic dive watches. I bought this model as it offers me accurate time keeping without the need to replace batteries. I’ve only had it a few months, but I love it …

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External references / further reading

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