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.
Note – all images courtesy of Seiko Watches (1)
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 over £3,000. The Seiko Prospex dive watch range represent the high end of build quality. The name itself stands for “Professional Specification”. In the Japanese market – the Seiko Prospex holds similar status to TAG Heuer, Rolex and Omega.
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Seiko Samurai – disctinctive styling
A very popular design from Seiko is commonly referred to as the Seiko Samurai divers watch. Named so from it’s distinctive bevelled lugs. The Seiko Samurai is a nickname that covers several Seiko watch models incorporating the case design shown below – the Seiko Prospex PADI – the Seiko SRPB99K1.
The Samurai dive watches have been tested to ISO 6425. It’s an affordable timepiece for everyday use and scuba diving. The Seiko Samurai is available only with an automatic movement – self-winding mechanism. Most models are driven by the Seiko calibre 4R35 movement – with 41 hour power reserve and an accuracy of +45 to -35 seconds per day.
SKX007 & SKX009 classic divers watch
The Seiko SKX007 and Seiko SKX009 were two of the most popular dive watches the Japanese manufacturer ever produced. First introduced in 1996 they existed in several guises. Older models can be identified by their 150m water resistancy, newer ones were certified to 200m.
Seiko SKX009 – with Pepsi bezel
A genuine classic – the original Seiko Pepsi dive watch – official title the Seiko SKX009 with it’s distinctive red and blue bezel. Available with either a steel bracelet or the more popular rubber divers strap.
The SKX007 and SKX009 are two of the most sought after dive watches on the pre-owned market. Maybe because it’s a serious diver’s watch with an ISO 6425 rating to 200m. It also features a uni-directional dive time bezel and a screw in crown.
Seiko SKX007 – black dial & bezel
Slightly less popular than the SKX009 is the Seiko SKX007 but mechanically identical. The single difference between these two models is down to colour of the watch dial and bezel. The Seiko SKX007 has an all black watch face and an all black dial.
The original SKX dive watches were rated to 150m. Later versions have an improved rating of 200m. Like the SKX009 – the SKX007 utilises the ever reliable Seiko Calibre 7S26 automatic (self winding) movement
The Seiko Prospex models have options for four movement types – automatic, quartz, solar – and Seiko’s own Kinetic movement. The majority of the Seiko dive watches are certified to a water resistancy of 200m (660ft) – although there are certain models rated down to 1000m (3,300ft). Many conform to the strict standards laid out in ISO 6425 Dive Watch specification
Not a term the marketing team at Seiko probably penned – but a nickname for this style of dive watch case. Many people look at the round, tall, lugless case design and think it resembles a Tuna can – thus the name Seiko Tuna dive watch
The Seiko Tuna is the professional diver’s watch of choice from the current line up. Suitable for saturation diving (where mixed gases including Helium are used) the Seiko Tuna is certified to depths of 1,000m (3,300 ft). Unlike most saturation dive watches – the Tuna does NOT have a helium release valve. In 1975 Seiko designed these watches with a unique and patented case and gasket that prevented helium ingress.
As Seiko’s entry level dive watches – the SKX007 & SKX009 were two of the most popular models ever produced. The new entry level models attempting to replace the iconic SKX range are often referred to as Turtle cased dive watches. This is due to their smooth rounded “turtle shell” / or “cushion case” design. The Seiko Turtle dive watch range offer an affordable entry in to the world of Seiko Prospex divers’ watches
Just like the SKX007/009 and their predecessors – the 6306 / 6309- the Seiko Turtle dive watch has the winder at the 4 o’clock position. Currently only available with Automatic movements (Seiko Calibre 4R36/4R35).
Limited Edition models
Seiko frequently release some highly desirable limited edition dive watches. Genuine low volume production runs of stunning watches.
High Beating Limited Editions
Seiko produce some of the most accurate, high beating watches in the world. By HIGH BEATING we mean that they “tick” up to 10 times per second. All mechanical watches can be categorised by their VPH / BPH. That’s their “vibrations per hour” or “beats per hour”. Dividing the VPH figure by 3,600 will give the “ticks per second”. Most luxury brand Swiss watches have 28,800 VPH movements – 8 ticks per second. Seiko produce some watches with a 36,000 VPH – giving a super smooth 10 beats per second. It’s these 8 and 10 beat per second Calibres that often power Seiko’s most expensive limited edition dive watches.
The watches shown above are all from Seiko’s limited edition commemorative lines. The SLA025J1 (Calibre 8L55 / 10 beats per second) limited to 1,500 pieces. The SLA019J1 (Calibre 8L35 / 8 beats per second) limited to 1,968 pieces. And the odd one out – the QUARTZ powered S23626J1 limted to just 1,978 pieces.
Entry level Limited Editions
What is pleasantly suprising is these limited edition models are not always the most expensive. Recent examples include the Seiko Prospex Black series from 2018 – shown below (sold for approx £370 / US$450). These all black dive watches with part codes – SSC673, SRPC49 & SNE493 (solar chronograph, automatic diver & solar diver with date bubble) featured a bright orange minute hand to accurately indicate the precise time. Seiko’s unique LumiBrite ensures reliable visibility even at the darkest depths
Seiko Watch Movements
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.
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)
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
- 4 beats per second | 23 jewels | 41 hours | +45 to -35 secs/day
- 6 beats per second | 23 jewels | 50 hours | +25 to -15 secs/day
- 6 beats per second | 23 jewels | 40 hours | +40 to -20 secs/day
- 8 beats per second | 26 jewels | 50 hours | +15 to -10 secs/day
- 10 beats per second | 26 jewels | 55 hours | +15 to -10 secs/day
- 6 beats per second | 23 jewels | 50 hours | +25 to -15 secs/day
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
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.
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.
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 …
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.
External references / further reading
- SeikoWatches (1) official website