Of all the Seiko ISO rated dive watches the Seiko Tuna has the most distinctive / original design. This unique design comes more from necessity than aesthetics. The key to this styling lies in the depth this watch can withstand. The Seiko Tuna range (that’s a nickname – not an official Seiko nomenclature) is a PROFESSIONAL diver’s watch capable of withstanding the pressure from depths of 600m (now 1000m). When diving at these depths a combination of mixed gases are used to protect the diver’s from “the bends” (1)
- The first quartz 600m dive watch – 1978
- Helium Escape Valve – not required
- Seiko Tuna Sales
- Current model numbers
- Video Reviews
Helium Release Valve – superfluous
A proportion of these mixed gases is HELIUM. And there lies the problem. Helium particles are TINY … really TINY. They are small enough to enter the casing of a watch water resistant to even 600m. The problem arises during decompression. The helium gas cannot get out quickly enough. There is a build up pressure inside the watch which may cause the glass to blow off.
Counterfeit warning – shoppers must make their own judgement to determine the authenticity of any watch before buying it – avoid buying a fake watch
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UK sellers – updated 21st May 2019
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USA Sellers – updated May 21, 2019
>>> more Seiko Tuna from USA sellers here
Titanium casing & special gasket
Seiko looked outside the box for solutions. Instead of looking to ways of allowing the helium to get out … they stopped it entering in the first place. With a specially designed gasket and the titanium monochoque casing the problem was solved in a unique fashion. That was back in 1975 that the world was first introduced to the Seiko Tuna. The initial watches were driven by Seiko’s 6159 Calibre (3) – 26 jewel – automatic movement.
First Quartz 600m Dive watch – 1978
In 1978 The Seiko Professional Diver’s 600M became the world’s first saturation diving watch featuring a quartz movement in 1978.
Driven by the 7549 caliber the Seiko Tuna was establishing itself as THE professional divers watch. To reinforce it’s superiority and prove it’s reliability Seiko undertook an amazing test. In 1983 the Seiko Tuna with 7549 quartz movement was was strapped to the research submarine “SHINKAI 2000” (5). Down it went to an official depth of 1,062 meters below sea level. That’s nearly twice the maximum depth this watch is rated to. Needless to say – the Tuna performed with perfect accuracy.
200m to 1000m
The current line up of Seiko Tuna can withstand dive depths from 200m to 1000m. Since their introduction in in the late 1970’s the Tuna has been produced with all available Seiko movements from automatic (self winding), quartz, kinetic and solar.
Seiko refresh their Prospex dive watches quite frequently. While writing this article (June 2019) there were just 4 versions of Prospex dive watches with the “Tuna can” style case. The S23627J1 and S23626J1 are both limited edition models with the 7C46 quartz movement. These two models are quite hard to find being collectors items. Prices range from £2,000 to £2,700. For a more modest budget of around £600 there is the SRPA83K1. With a water resistancy of 200m – driven by the 4R36 automatic movement.
My personal favourite is the Seiko SBDX014G. This Marinemaster professional dive watch is certified to 1000m. For £3,250 you get the luxurious mechanical calibre 8L35 automatic movement. 26 jewels providing an accuracy of +15 to -10 seconds per day and a 51 hour power reserve.
Available online now
Chronodivers.com is an affiliated partner of Amazon.com. Here’s a selection from their range of Seiko 200m dive watches (not specifically the “Tuna” case style)
Ceramic/titanium (hard coating) with stainless steel bezel
Automatic with manual winding capacity
Approx. 50 hours
+15 to -10 seconds per day
Lumibrite on hands and indexs
1000m / 3300ft for saturation diving
- 26 jewels
- Date display
- Screw-down crown
- Stop seconds hand function
- Unidirectional rotating bezel
Seiko Tuna Videos
Seiko Prospex Marine Master Professional SBDX014G
Peter Alexander Manthos – his take on the Seiko Prospex Marine Master Professional SBDX014G
Seiko PADI Monster Tuna – SRPA83K1
Watch Videos – a full review of the PADI baby Tuna 200m dive watch
External references / further reading
- (1) EmedicineHealth.com : The Bends – decompression sickness
- (2) MonoChrome watches : Hisory of The Seiko Tuna
- (3) Fratello Watches : The history of the Seiko Tuna
- (4) The Springbar : Seiko Tuna Collectors guide
- (5) SeikoWatches : Prospex Dive watch history
If you found this page via a search engine – please pop over to our generic Seiko Divers watch page. You will find plenty more information on iconic styles from Japan’s leading manufacturer of quality dive watches.