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seiko tuna mod for sale


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Delivery time on pre-orders takes around 30 business days

Seiko Tuna Black

seiko tuna black dial

$ 370.00

Black Submariner bezel

Black Seiko dial

Sapphire cyclops glass

Seiko NH35 movement

Stainless steel case 40mm

Glidelock clasp

Seiko Tuna Blue

seiko tuna blue dial

$ 370.00

Black Submariner bezel

Blue Seiko dial

Sapphire cyclops glass

Seiko NH35 movement

Stainless steel case 40mm

Glidelock clasp

Seiko Tuna Cherry

seiko tuna cherry dial

$ 370.00

Black Submariner bezel

Cherry Seiko dial

Sapphire cyclops glass

Seiko NH35 movement

Stainless steel case 40mm

Glidelock clasp

Seiko Tuna Green

seiko tuna green dial

$ 370.00

Black Submariner bezel

Green Seiko dial

Sapphire cyclops glass

Seiko NH35 movement

Stainless steel case 40mm

Glidelock clasp

Seiko Tuna Orange

seiko tuna orange dial

$ 370.00

Black Submariner bezel

Orange Seiko dial

Sapphire cyclops glass

Seiko NH35 movement

Stainless steel case 40mm

Glidelock clasp

Seiko Tuna Samurai

seiko tuna samurai dial

$ 370.00

Black Submariner bezel

Samurai Seiko dial

Sapphire cyclops glass

Seiko NH35 movement

Stainless steel case 40mm

Glidelock clasp

Seiko Tuna Submariner

seiko tuna submariner dial

$ 370.00

Black Submariner bezel

Submariner Seiko dial

Sapphire cyclops glass

Seiko NH35 movement

Stainless steel case 40mm

Glidelock clasp

Seiko Tuna 300MM

seiko tuna 300mm dial

$ 370.00

Black Submariner bezel

300MM Seiko dial

Sapphire cyclops glass

Seiko NH35 movement

Stainless steel case 40mm

Glidelock clasp

Seiko Tuna mod gallery

seiko tuna 300mm 2
seiko tuna 300mm 3
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seiko tuna black 4
seiko tuna blue 7
seiko tuna cherry 2
seiko tuna cherry 1
seiko tuna cherry 3
seiko tuna cherry 4
seiko tuna cherry 5
seiko tuna cherry 6
seiko tuna cherry 7
seiko tuna green 1
seiko tuna green 2
seiko tuna green 3
seiko tuna green 4
seiko tuna green 6
seiko tuna green 7
seiko tuna green 8
seiko tuna submariner 1
seiko tuna submariner 2

Seiko Tuna mod parameters

seiko tuna mod for sale

SEIKO Japanese NH35 movement

Case diameter

46.5mm (excluding crown)

47.2mm (with crown)

The thickness of the case


Strap width


Watch structure

Compact one-piece casing, screwed back cover and barrel

Waterproof depth

We don't give guarantee, only on your responsibility

Available Seiko MOD models

Buying a Seiko Tuna watch



The Seiko Tuna is one of the most popular watches of all time in the Seiko line. It is because of a lot of reasons, particularly because it is very pretty and aesthetic. Seiko Tuna is the name that has been given to watches that were specially designed for professional and scuba diving. Seiko has made these watches with specific conditions in mind. They were made to withstand high pressure and saturation that might occur when diving. Since they have protective screwed-on shrouds, they were given the name Tuna.

The Seiko Tuna has four major variants: the 6159B, 7549A, 7C46, and 5M23. The 6159B is known as the grandfather tuna and was the first one in the series. The following two were called Golden tuna because of their gold-tinted shrouds. Lastly, the most recent one is called Baby tuna. The range of watches in this collection has a lot of great things, such as being the first ceramic-coated titanium shroud in the Seiko line. It also has an L-shaped gasket, a monocoque case as well a rubber strap. While it was built for its functionality, it is also very pleasing to look at.

Seiko Tuna Timeline


Brief history

The Seiko Tuna watch was created to respond to a complaint letter that the company received back in 1968. A saturation diver in Hiroshima, specifically from Kure city, said that the previous lines of Seiko divers watch, which was made in 1965, were not good enough to withstand the exposure to underwater pressure for a long period of time. Divers watches are constantly subjected to extreme conditions, and that is why the watches need to have unique characteristics to be able to do that.

When this happened, Ikuo Tokunaga, along with his team has then started developing the best professional diver’s watch there could be. The engineering team of Seiko took the complaint letter as a challenge so that they would be able to make the best watch that can help professional divers. They started developing a new watch which would then become the first in the series of Seiko Tuna watches.

Different watches in the Tuna series

The first watch in the Tuna series, the 6159-7010, was run through mechanical movement. It was used by 300m divers, and it was the first of many things. For example, it was the first watch to have a titanium monocoque case with a shroud covered with ceramic. It is also the first to have an L-shaped gasket that has a vented rubber strap.


This Grandfather Tuna watch by Seiko has an escape valve which is a mechanism that was first devised by Rolex, which allows helium, hydrogen, and other gases to be released from being trapped inside the case easily. It features a one-piece case that has a crystal restrained through a locking ring. The screw-drown crystal has then earned it the nickname of a tuna can. A lot of other collectors prefer to call it hockey puck. The watch has passed ISO testing standards for watches, which meant a lot since passing the standards that ISO sets are a big deal. It means that it passed a resistance test to pressure, shock tests, extreme temperatures, and more.


As most collectors would call it, the Golden Tuna is another popular model in the Tuna series. This was even made more popular when it got featured in a James Bond movie titled For Your Eyes Only. The watch is visible in an underwater shot, and the watch was manufactured until 1978. It is one of the most popular watches of all time and can be considered worth it given its features.

For example, to have it look different from the previous model, a nitride coating was given to it to give off a golden color. This is the reason why it is called the Golden Tuna. It is also distinguishable by its size since it is smaller than the previous one at 49mm.

It is still a mystery why Seiko got rid of all the gold accents to replace it with an all-black case, but the Star wards fans were swift in associating it with their favorite character of all time; thus, the watch earned the name Darth Tuna. It has a high resistance of 1000m which was 400m more than its predecessor.

After a few reissues of the Golden and Grandfather Tuna, in 2009, the Seiko Tuna series was added with a new one. It was called the SBDX011 Marinemaster Automatic Professional, and not long after its release, it was given the name “Emperor Tuna.” It came with some upgrades, such as the sapphire crystal being used instead of the Hardlex one. IT had a 52mm case covered with titanium to protect it even when going through the depth of 1000 meters.


Also known as the Ultimate Tuna, the Golden Spring Drive Tuna of the Seiko Tuna line collection is one that really deserves its name. It is the combination of the Grand Seiko and the tuna line which makes it even more special. It was released on the 100th year anniversary of the Tuna line, which was back in 2013. It was very special to the point that it was a limited edition with only 300 pieces sold. The movement of this specific watch is impressive, and it boasts a hybrid of quartz and automatic movement. The best part is that it has a 72-hour power reserve and has a high accuracy rating.

Parts of the Seiko Tuna

Now that you have a brief overview of some of the tuna watches, the next part would be all about the details, specifications, and features of the watch, which would help you learn more about it further. This will give you a better understanding of what is happening so that you will have an idea of how to look for the one that fits you best.


The Tuna line has four main movements: the 6159B, 7549A, 7C46, and the 5M23A. All of them were created by Seiko engineers themselves. They are all in the range hacks and can be hand winded. They run at 36,000 BPH. The movement 7549A quartz is on the mechanical side, and this makes it more robust. On the other hand, 7C46 runs on five-year battery life and has a very reliable movement. The 5M23A, on the other hand, runs on kinetic quartz movement and uses the arm movement of the person to generate electrical energy to power it up.



Another thing to know about would be the dials of the watch. The Tuna line can easily be characterized by its black dials as well as its LumiBrite lume. It is a feature that is known to indicate hours using markers instead of numbers. All the tuna watches have Seiko written on all of their dials. They also have the water-resistance indication as well as the number of meters of depth they can reach. While there are no subdials in any Tuna watches, they have some that show the date.


If you notice, the Seiko Tuna has a can-like design which is where it has derived its name. This is because of the round monocoque case that is made of titanium that protects the watch itself. One thing that would set one model from the other would be the color of its shroud. This is because most of the time, the shroud changes colors from one variant to the other.


You would want to know that most of the watches in the Tuna range have Hardflex crystal. However, the Golden Tuna uses a domed Hardflex, while the Darth Tuna uses a sapphire one. The AR properties of this are easily shown through the blue reflections that it gives off.


All the watches in the Tuna line have a uniform unidirectional rotating bezel. It means that it quickly shows the divers how many minutes they have spent underwater. The watches are very precise, so you would not need to worry about them at all.


When you want to buy something, you need to understand what you are buying and its worth. The Tuna collection is what you want to buy, and that is why first you would like to know the features, and then you can easily decide if it is worth the money you will be paying for.


What started as a complaint that was being answered turned into something more than it seemed. The Seiko Tuna line collection proves that something can improve as fast as possible when there is a dedicated team. If you are looking to buy one, here are some of the recommended ones from the line that you are sure to love.

Seiko Arnie Tuna

This one is quite popular, especially since it has a lot of Hollywood screen time too. IT was because Arnold Schwarzenegger picked it in both movies, Commando in 1985 and Predator in 1987. It is named after him as well, which is why it is called Arnie. The best part is that it is one of the world’s first analog-digital watches.


It might look like a regular watch from the collection, but you will see an LCD at the top portion of its dial that would let you set your second timezone. This means that you get a dual timezone by using this watch. It also has an alarm and a chronograph which makes it unique and sets it apart from all the other watches.

For its movement, it uses the quartz caliber, and it is known to be solar-powered too. This means that there is no need to change its batteries since you can use the sun to charge it up. It has a water resistance of 200m, and its size is 47.8mm. You would want to consider them when you are deciding whether to buy them or not.

Seiko Ashtray Tuna

This might not sound as entirely pleasing, but the features are worth it. It looks a little different from most of the lineup from this line, but it shares all the reliability and durability of the other Seiko tuna watches. With its titanium bezel having oval recesses, it looks like your regular ashtray, thus its name.


While not most people might get impressed with its design, the specifications are enough to make their jaw drop. The first is that it is capable of 600m water resistance. It is also essential to know that it is only 45 mm in diameter, which is not too large. If you are looking for a watch that will also provide you with comfort and durability, then this is undoubtedly what you are looking for.

It is known to be antimagnetic and can handle the extreme temperature. It uses quartz for its movement, and it has a titanium case perfect for your daily use. You will be able to expect this watch to last you for some years, give or take.

Seiko Monster Tuna

The Monster tuna in the Seiko Tuna line is one of the best choices that you can get as it is a crossbreed between Seiko’s monster line and the Tuna line. The watch screams how gorgeous it is with its metallic blue and red colors. It is an excellent way of showing Seiko’s collab with the PADI or the Professional association of diving instructors. By this, you are ensured that the watch is good enough for its purpose.


The watch also comes with a slip-resistant strap that makes it far more durable to wear. You would not have to sacrifice your comfort either since you can easily wear it on top of any of your diving suits. You can also fit it under your sleeve if that is what you want. The case is made of stainless steel, has a dimension of 50mm, and is water-resistant up to 200m.

Seiko Baby Tuna

The youngest in the Tuna line is this one, but the name does not imply it for kids. It is actually a very affordable watch for professional divers. It has a large case at 50mm, which is pretty large compared to other watches. It has a stainless bezel that is covered in ceramic to give it a better look.


The curved design of this watch helps to increase comfort when wearing it. It also has lugs that are short to feel smaller than how they actually should be. It has a self-winding movement and has a power reserve of around 41 hours. It is water-resistant up to 200m.

Seiko Tuna Can

You would want to think twice before buying anything that looks good, but if you are planning to get a watch, the Tuna can is a good choice. Its silver case is 48mm in size, which is quite large, but it has a Hardlex crystal screwed to its case, which improves the resistance of the watch to the pressure of the water below sea level.


Although it is on the big side, it is surprising that the watch is very comfortable to wear. It is not only suitable for your diving experience but also for your daily use. It is powered by a quartz movement and has a battery life of 5 years. It is water-resistant up to 300m.

Seiko Tuna PADI Edition

The blue and red scheme of the Seiko Tuna PADI special edition is something that you would really love. It has a beautiful color scheme that sets it apart from all the other watches out there. It is approved by PADI and is actually a collaboration of Seiko with them. It has a wave pattern on the black part of the dial, has a date function. It can also be a quick start, has overcharging prevention, and is water-resistant up to 200m. it is solar-powered and is known to operate up to 10 months if it is fully charged. The case is made of stainless steel, and it is 46.7mm in size.


Seiko Tuna Save the Ocean

This edition of the Tuna line is known because of its marine conservation theme. It has a navy blue bezel representing water. The dial features are also horizontal that are meant to represent waves. It is known to be powered by a quartz movement. It is also solar-powered, so you would not need to charge your battery for a while. It can power up the watch for about ten months without needing to charge it up. There is an ocean wave-shaped engraving at the back of the watch as well. The case is made of stainless steel, and it is 46.7mm large and is water-resistant up to 200m.


The Seiko Tuna is one of the lines that Seiko is very proud of when it comes to diving watches. It is created out of the passion the engineers of Seiko have to satisfy their customers, and it has come a long way since then. The design might not be everyone’s cup of tea, but it certainly is a huge seller. It is one of the best diving watches out there, and that is undeniable.


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What is Seiko Mod Shop?

Seiko Mod Shop is one of the world's leading service companies for the customization and personalization of Seiko watches. An experienced team of specialists transforms from the bracelet to the dial - according to individual customer requirements. All our designs have Seiko automatic or quartz movements inside. Also upon request, we can discuss any other modifications and an individual movement.

How do preorders work?

A pre-order is an order placed for an item that hasn’t been released or is not currently in stock. They’re shipped to the customer once available. Pre-orders allow customers to order products before they are available.

Can I change or cancel my order?

Our customers have 24 hours to change/cancel an order.

Please contact us immediately by email: [email protected] ; if you need to make any changes or cancel your order.

For order canceling we charge additional fee 35 USD per each order.

If more than 24 hours have passed, due business specification we cannot issue order cancel/change, as all of our products are exclusively on pre-order - we order all the necessary spare parts for each client individually.

How can I track my order?

Once your order has shipped, you will receive tracking information via email. If you haven’t received an email, please contact us and we will resend you the tracking information.

What should I do if my tracking number is not working?

New tracking numbers usually take about 24 hours to activate from the time you receive your shipping confirmation. If it’s been more than 24 hours and your tracking number still isn’t working, contact us and we’ll help ensure you get your package!

When will I receive my order?

We ship within 35 business days after placing an order. Delivery takes about 30 business days, all depends from your country and post office workload. But in practice we deliver orders faster.

Will I need to pay taxes and duties?

We are not responsible for Import duties, but we can help and provide smaller invoice to avoid big tax payment

Returns and exchanges

It’s a custom made items done on pre order. All sales final, items are sold as is. Final sale items cannot be returned, exchanged. No warranty and returns.

Watches in Stock!

Delivery 3-7 business days