Seiko Tuna Dive Watch

Seiko Tuna Professional Divers Watch Reviewed by ChronoDivers

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The Seiko Tuna is a professional diver’s watch that can withstand depths up to 1000m. From the globally popular range of Seiko diver’s watches this is the one certified for the deepest dives. Join us as we take a deep dive into this deep diving Seiko Diver’s Watch. A review of the Tuna’s key functions & features and where to buy a pre-owned Seiko Tuna dive watch.

Introducing the Tuna Diver

The Seiko Tuna, also known as the Seiko Professional Diver’s 600m, is a dive watch that has become a legend in the watchmaking industry. The watch is named after its unique shape, which resembles a can of tuna due to its protective shroud that covers the case and crown. The Tuna watch was developed to protect the watch from potential damage during deep-sea diving, and its design has since become a defining feature of the watch.

Professional Dive Watch – 1975

The Seiko Tuna was first introduced in 1975 as a response to the growing demand for professional dive watches. At the time, Seiko was already well-known for its dive watches, but the Tuna represented a significant advancement in dive watch technology. The watch was designed to meet the needs of professional divers who required a timepiece that could withstand the extreme conditions of deep-sea diving.

Helium Resistant Shroud

One of the most significant features of the Seiko Tuna is its shroud, which is made of durable, corrosion-resistant titanium. The external gasket / shroud covers the case and crown of the watch, providing an extra layer of protection against scratches, impacts, and other damage that can occur during underwater activities. It also acts, most importantly, to keep Helium gas out. The shroud also gives the watch its distinctive shape, which has become synonymous with the Seiko Tuna.

How Deep? 600 to 1,000 meters

The “standard” Seiko Tuna is water-resistant up to 600 meters (2000 feet), making it suitable for deep-sea diving. The watch features a unidirectional rotating bezel, which is used to time dives. The bezel is easy to grip and turn, even when wearing gloves, and it provides an accurate measurement of elapsed time during a dive. If you’ve got in excess of £2,000 then you can find some 1,000 meters versions of the Tuna.

In conclusion, the Seiko Tuna is a dive watch that has become a legend in the watchmaking industry. The watch is known for its unique design, durability, and reliability, making it a popular choice for professional divers and watch enthusiasts alike. The Seiko Tuna is a testament to Seiko’s commitment to precision, innovation, and excellence in watchmaking.

Seiko Tuna for Sale

eBay is a popular starting point in many buyers Tuna watch journey. To browse all the Seiko Tuna watches available today – simply click the blue button below for a carefully FILTERED selection.

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Tuna Divers found on eBay

All the watches below were found on eBay. eBay is a great place to go to check a) the current prices of a specific watch and b) to see what the watch looks like in the “real world”. Most product photos on eBay are taken with great care to best represent the watch. You get to see what it really looks like (not a computer enhanced brochure photo). Browse more Seiko Tuna just like these > visit eBay* now

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No Helium Escape Valve

Of all the Seiko dive watches the Tuna has the most distinctive / original design, in fact, possibly of all the dive watches on the market (exception Omega PloProf). This unique design comes more from necessity than aesthetics. The key to this styling lies in the depth this watch can withstand.  When diving at extreme depths a combination of mixed gases are used to protect the diver’s from “the bends”.

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 1000m. 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.

Patented Gasket Solution

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 monocoque 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 – 26 jewel – automatic movement.

Seiko Prospex Tuna Marinemaster 1000M Automatic Watch SLA042J1/SBDX038 DE*de

In 1978 that the Seiko Professional Diver’s 600 became the world’s first saturation diving watch featuring a quartz movement. Driven by the 7549 calibre the Seiko Tuna was establishing itself as THE professional divers watch. In fact, to reinforce it’s superiority and prove it’s reliability Seiko undertook an amazing test.

In 1983 a Seiko Tuna with the 7549 quartz movement was strapped to the research submarine “SHINKAI 2000”. Accordingly, down it went to an official depth of 1,062 meters below sea level. To emphasize, that’s nearly twice the maximum depth this watch is rated to. Needless to say, the Tuna performed with perfect accuracy. Due to this outstanding performance the Tuna booked it’s place in the Dive Watch Hall of Fame – and for very good reason.

1000m Tuna Marinemaster

The example shown below is a Limited Edition Quartz Seiko Tuna Marinemaster – water resistant to 1000m. This one is quite rare, notice the white ceramic helium escape gasket. For the record it’s a Seiko SBBN019 also known by it’s nickname as the Seiko White Dolphin (sometimes the Beluga or even the Storm Trooper). It was produced to celebrate 45 years since the first Tuna diver’s watch. Being one of a very limited run of just 300 timepieces – this one would fetch a premium if it were sold today – somewhere in the region of £1,750 / $2,000.

Seiko Tuna sbbn019 prospex 1000 m

Steeldive “Tuna” homage

Customers who admire the aesthetics of the Tuna dive watch may also like the Steeldive Tuna tribute – the SD1975. Not a fake, moreover a respectful and affordable tribute to this innovative dive watch.

Tuna Nicknames

The Tuna range is littered with witty nicknames. Here’s a few: the Darth Tuna (all black version), Mini Tuna (correct, it’s a bit smaller) , Emperor TunaYellow Tuna (yellow bezel and accent on hands) all the way back to aptly named original Grandfather Tuna. Another popular name for the regular version of this watch is the Seiko Baby Tuna. The “baby” refers to the fact that it’s a slightly under-engineered version of the professional MarineMaster version.

Seiko Baby Tuna SRP637K1 with 4R36 calibre automatic movement


What to pay for a used Tuna

A question we get asked everyday for practically all the watches listed on the website. It’s all down to popularity, rarity, provenance and condition. Let’s start at the TOP end of the market. Don’t forget these watches are some of the finest timepieces in the world – in my view equalling the quality of some Swiss brands.

The Seiko SBDB013 Spring Drive Tuna Marinemaster is not going to give you any change from £2,500. If it says MARINEMASTER on the dial and it’s genuine, the starting price has to be around £1,000 / $1,000+ for a “basic” automatic model. However, there are plenty of other versions available in particular, the solar and street Tuna models starting at £250.

Seiko Divers on Amazon

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Further Reading