History & Information of Seiko Divers Watches

The Seiko SLA017 - a re-interpretation of a Vintage Seiko 62MAS divers watch originally introduced in 1965

Note – all images courtesy of Seiko Watches (1)

A hugely popular watch range among recreational and professional divers offering excellent value for money and high standards of Japanese quality assurance. My personal favourite is the Seiko SLA017 (headline image) – 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.

Seiko Prospex Dive Watches

Where are we today … 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”. For the true professional diver there is just one watch – the Seiko Prospex Tuna comes in 1000m water resistant models thanks to it’s external helium gasket. In the Japanese market (and growing worldwide) Seiko’s premium label watches hold similar status to TAG Heuer, Rolex and Omega.

Watch of the Day 👌

A Seiko Dive Watch discovered on eBay today. Click “Read more” for details on this specific watch or click here for all Seiko Dive watches listed for sale today

£430.00 (Used)

🇬🇧 DELIVERY : Seiko King Samurai SRPE37K1 Men’s Prospex Automatic Date with box and papers. This watch is available now for £430.00. The seller is located in GB. The condition of this Divers Watch has been li…

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

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 diver’s watch with years of manufacturer, important notes and some popular model numbers (eight digits eg 7S26-5678).

1st Generation – Seiko 6217

Model reference Seiko 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 divers watch in original condition
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

2nd Generation – Seiko 6105

Model reference Seiko 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 classic and slightly battered Seiko 6105-8000 divers watch
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

3rd Generation – Seiko 630X

The main difference between the Seiko 6306 and 6309 dive watches lies in their movements. The Seiko 6306 features a hacking movement, allowing the seconds hand to stop when the time is being set, aiding precise time adjustment. In contrast, the Seiko 6309 lacks this hacking feature, making it less convenient for accurate time setting. Both watches belong to the iconic Seiko diver series, renowned for their durability and water resistance. Enthusiasts often appreciate these vintage models for their robust design and historical significance in the realm of dive watches.

Seiko 6306 (ORIGINAL 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 “Seiko Turtle” case design makes an appearance. All models show “WATER 150m RESIST” on the dial

A vintage Seiko Divers watch - this is a Japanese Seiko 6306-7000 showing aged patina
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 (original Turtle) -black dial, 60 click, bi-directional black bezel. “Japan 6306” on dial between 6 and 7 o’clock.

Seiko 6309

Model reference 6309 (mainly International market) – Years in production: 1976 to 1988. Water Resistant: 150m. Black bezel only. Movement: Calibre 6309 automatic (self-winding) movement with 17 jewels running at 21,600bph. This 6309 movement is non-hacking and cannot be hand wound. All models show “WATER 150m RESIST” on the dial. Seiko Turtle is a collective term that covers all the 6306 and 6309 Seiko diving watches with the cushion shaped case. Looking to buy one? We have a selection of Seiko Turtle for sale here on our dedicated sales & information page

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

The watches listed below each have their own information and history page. So influential and innovative are they all, each watch deserves it’s own dedicated HISTORY & INFORMATION page.

4th Generation – Seiko 7002

Model reference Seiko 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 well used example of a Seiko 7002-7000 dive watch
A vintage Seiko 7002-7000 dive watch – courtesy of eBay seller Legend of Sellda

MKI 7002 – 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 7002 – 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.

5th Generation – Seiko SKX

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 very popular divers watch - the Seiko SKX007 in a 7S26-0020 case
A Seiko SKX007 7S26-002X – courtesy of eBay seller defaultguy01

Seiko 7S26-0020 Dive Watches

  • 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
The most popular of all - the Red and Blue bezel of the Seiko SKX009 with the nickname Seiko PEPSI
An example of a Seiko SKX009 200m diver’s watch – courtesy of eBay seller WatchNationShopLtd
  • 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 (self winding)

A Seiko automatic dive 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 modern Seiko watches also allow for “hacking” – the manual winding of the watch to give it a head-start.

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 about 10 winds (back and forth)

We use the Seiko made NH35A in our Dive Watches

When specifying the build of our own CD200SKX dive watch we opted for the SII NH35A automatic self-winding movement (a Seiko company). With 24 jewels, a 40 hour power reserve and hacking plus quick set date – it’s an excellent partner for our watches. Pop over to ChronoDivers.co.uk to visit our UK STORE.

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

  • 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

Solar Powered Seiko Movements

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

Kinetic powered Seiko watches

Whereas a solar powered watch charges the battery from energy stored within light – a Seiko Kinetic divers 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 – pedaling spins the dynamo which in turn charges the batteries which in turn power the light.

The END of Seiko Kintetic Watches

Seiko have stopped production of the Kinetic movement. Entry level watches will be powered by either a Solar or Automatic movements. The most expensive models feature the GROUNDBREAKING Seiko Spring Drive technology. This is a real game changing technology. 99% mechanical with just 1% of the watch, the regulator as such, keeping track of the time. If you want the very best of the best – it has to be a Spring Drive diver like the Seiko SNR029 from the LX Line (about £5k +)

Quartz watch movements

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.

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 already know it’s a keeper, just like my Bremont Supermarine S500 shown in the middle.

Seiko Divers on Amazon 🙏

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