Buying a (Seiko) Tuna

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Recently, at a casual gathering of watch enthusiasts, most of who prefer refined automatics under or around 40 mm, there was an undeniable attraction to two Seiko SBBN015s (48mm cases and quartz powered) that had made their way into a pile of Sinns, Damaskos, Squales and vintage Hamiltons.


The seemingly garish Seiko shrouded divers has caught the attention of most of the table sharing Neapolitan pizza pies and watch talk. The Seiko “Tuna” nicknamed for its Chicken of the Sea-style circular case is most definitely unique and it’s an eye-catching design that also happens to be derived from some serious dive watch innovation by the Japanese watch manufacturer, whose history in the development of dive watches is on par with the biggest names in the category.

The shroud is a shield for the case that is secured with three screws, giving the suit-of-armor appearance that projects an all-business attitude that fans love. Two cut outs give the wearer access to turn the timing bezel.

image source: WUS user Roberto Jaksic
image source: WUS user Roberto Jaksic

Watch out for Tuna fever. It’s contagious.

I won’t go deep into the history, but the beginnings of the Seiko shrouded diver go back to 1975 with the introduction of the 6159-7010, which is known as the Grandfather Tuna. It’s a magnificent watch that features a titanium case, L-shaped crystal gasket, ceramic-coated titanium shroud, automatic movement and no helium escape valve. Seiko was at the time seeking to create a watch that could hold up well for professional saturation divers and came up with the first Tuna. The modern version is nicknamed the Emperor Tuna, the SBDX011, which retails for around $2,300 and uses an undecorated Grand Seiko movement, the 8L35.

The first quartz Tuna was the 7549-7009, also known as the Golden Tuna for its gold colored accents. Released in 1978, the 600-meter rated watch was Seiko’s first quartz diver meant for professional diving.


For the me the Tuna series hits its sweet spot at the 300 meter depth-rated quartz Prospex models, the SBBN015 and the SBBN017, both well under $1,000 with the current exchange rate at the time of this article’s publication. If you’re a worn&wound reader who’s thinking, “Why would I pay over $500 for a quartz watch?” then you probably haven’t held a Tuna in your hands or strapped one on your wrist.

Here are 10 reasons (or excuses) for adding a Tuna to your collection:

  1. There’s nothing else like it at all. It’s a conversation starter and it’s so unlike a typical diver in appearance that no one will mistake you for wearing a Sub clone. But it still maintains traits that show its relationship with the rest of the Seiko diver watch heritage.
  2. It has historical significance and it’s part of the Seiko dive watch lineage.
  3. It wears a lot smaller than its specs because of the short lug design.
  4. The 7C46 high-torque quartz movement is designed specifically for this model. It can be serviced and uses a 7-jeweled gear train and dual-rate trimmers for maximum efficiency.
  5. In my experience, Tunas are very accurate and have a battery life lasting over five years. An end-of-battery-life indicator will show the seconds hand ticking at every two seconds to show it’s time for a battery change.
  6. The build quality rivals far more expensive watches. The printing on the dial, unique brushed hands, the smooth bezel action and sublime crown feel make it a joy to look at and operate.
  7. They wear well with every type of strap, from Isofranes to OEM bracelets to mesh to nylon to canvas to leather. The drilled-through lug holes make swaps easy too. Mine, for the most part, live on really broken-in Maratac Zulu straps.
  8. The Kanji days of the week are just plain cool.
  9. The lume is killer.
  10. It’s very durable and looks even better after it’s been through some watersports action.

Also, Seiko has unveiled new Tuna models (which don’t have the now-classic hands) and the rumor mill is brewing that the classics will be discontinued.

For those who can’t decide between the SBBN015 (black bezel insert) and SBBN017 (stainless steel bezel insert), I don’t think one is better than the other.  It’s a matter or preference.

image credit: seiyajapan

The SBBN015 (around $900) has an engraved black bezel insert, a very high-quality Oyster style bracelet with a ratcheting clasp and special end links made to fit the case (which retails for $280 on its own). The shroud has a brushed finish and the bezel itself has a different edge than the one on the SBBN017 (around $650). The 017 has a steel insert and a bead blasted shroud and comes with a rubber strap, which I also find to be comfortable. For those on the fence, I’d say people who enjoy their watches on a made-for-the-watch bracelet should go for the SBBN015 and those who have a lot of black bezel divers should go for the SBBN017.

Here are a few notes to those considering a Tuna:

  • The shroud is removable pretty easily. Just make sure you use nicer hex wrenches. You can send it off to have it DLC or cerakote coated for a stealthy look.
  • The crystal is doubled domed and made with Hardlex, Seiko’s proprietary material, which is purported to be more shatter resistant but less scratch resistant. Aftermarket sapphire crystals are available from or Yobokies, known purveyors of aftermarket Seiko watch parts.
  • There are even aftermarket shroud screws available from Andy Stockley, a member on the Seiko and Citizen Watch Forum. Check out our Modding 101 for more on that.
  • The Darth Tuna (SBBN013) is a highly desirable piece for those who like the all-black look. It features a monocoque case and flat sapphire crystal and the case has integrated lugs into the case. It retails for about $1,800.
  • The Spring Dive version is what some would consider the ultimate Tuna. The SBDB009 uses a 5R65 Spring Drive movement, which in the most simplified sense is an electronic assisted automatic movement to provide very high accuracy. It retails for just over $2,700.

I’ll acknowledge that Seiko offers other shrouded divers, but I would suggest you skip those and simply save for what collectors call “real Tunas.” Seiko sells automatic shrouded divers using its entry-level hacking and hand-winding 4R36 movement. The latest Prospex entries are the SRP655K1 (black) and SRP653K1 (blue), and both retail for just over $600.


The Kinetic GMT shrouded divers, including the SUN019 we’ve reviewed at worn&wound, and its brethren are another option if you want a diver with a shroud, but, again, these are not truly part of the Seiko Tuna lineage that started with the Grandfather Tuna.

So what are you waiting for? Tuna fever is spreading. Just accept it.

Images from this post:
Li's first watch was a $105 Seiko 5 dress watch. That purchase started his obsession, though he has since moved a bit more upmarket. Today, Li is a fanatic for Seiko divers, both vintage and new, with a special appreciation for the Seiko Marinemaster 300m.
  • Andrea Alfieri

    I wouldn’t trust people gathering around Neapolitan Pizza, might be part of the Mafia or something. The fact that the article author’s name sounds very italian confirms my suspicion.

    • Li Wang

      Ciao, Andrea. Did you forget your Tuna on vacation?

  • Jeffc2

    Lovely watch, but I cant get over the second hand tick…tick…tick…

  • Andrea Alfieri

    I might or might not have purchased an sbbn017 after reading this article. And I already own an sbbn015.
    I hate you wornandwound.

    • Li Wang

      I long them both and sometimes think I should have the 017 instead of the 015 because the silver bezel would be stand out within my collection. Can’t wait to see it, Andrea.

  • Li Wang

    Thanks for the update, Michael, on the new releases and whether or not the current models will continue. I really enjoy my SBBN015 and 7549-7010. Yet I am still looking forward to seeing what the next generation of Tunas brings. I’ve read the new lume is very strong, though I, personally, am not a major lume junkie.

  • Sealy57

    Love the tough, no nonsense look. Just looking at it caused the hair on my chest to grow half an inch.

  • AlaskaFreddy

    I have read a lot about dive watches from people who don’t dive. One person even said that it was ugly. The Tuna’s beauty is in it utility, and in its utility is its beauty. An armchair Captain Nemo will probably no understand the Tuna. The Tuna comes into its own in very deep and very dark water and at very deep night dives. Down there, in the halls of the great black blue, the Tuna speaks to the diver in a why other watches just can’t. You have to go down there, way, way down there and see the face and how big it looks to you when and where you must know exactly what time it is. On the edge of the abyss you not have the energy or time to “search” for the hands. Down there, you want the hands of your watch to come up off your wrist and tap you on the nose.

    • JNN

      The audience’s approach to the Tuna has and will always be bipolar, and has nothing to do with whether or not they dive. (I bet you more owners and fans of the Tuna are not divers than are divers.) This fact contributes to the Tuna’s popularity within the watch-enthusiast community. You either hate it or you love it, and this won’t change whether you wet-dive or you desk-dive. So there’s no need to denigrate anyone’s taste. I personally love the Tuna’s long-standing individuality and technical competence, no matter if it’s called by some as masculine or ugly.

    • jaypea

      Well put Sir. This this is the essence of a good dive watch.

      • AlaskaFreddy

        I wish that we could take all the folk who love the assorted, varied functional “dive” washes and put them in charge of a dive boat somewhere on or near the equator, and let only the new divers with their new dive watches sign up for the dive. Then, with tide and current just right, say, “Please set your dive watch to the time on the Dive Masters watch, thank you.” Then, with it about 90 degrees / 32 C, sit back and watch how much time it actually takes for the whole dive group to adjust their “dive” watch. Let’s see, 20 people X 2 minutes! Oh, I forgot, these are relatively new divers and that watch on their wrist is relatively new and it has 20 functions. Lol! Oh, who actually sets their dive watch to the dive master?

  • AlaskaFreddy

    I promise to come up to at least 20 meters before I try to spell!

  • Joselito

    Sir I bought seiko prospex SRP653k1 but i hate the straps when i perspire specially that I live in the phils. it sticks to my skin, so i plan to buy a steel strap of seiko diver 6309 stainless strap 22mm. Now my question is, is the strap can fit to case of the watch? tnx. God Bless..

  • miguelhilario

    Well, they just stuck a PADI monicker on your favorite watch. I was going to buy a sbbn 035 until I saw it the PADI version online. To me that means it’s not a true Marinemaster professional and cheapens the nobility and heritage of the name. I’m a tech and cave diver myself and although I have an old basic PADI open water cert, I wouldn’t want “PADI” slapped on any of my watches, let alone a Marinemaster. Definitely no such thing as a PADI commmercial saturation diver certification. Professional indeed.

  • Joe Deats

    Well written and interesting series of articles this one is a nice addition to your wonderful series on what many consider the best watch made for the money. I’m not a diver but I do require a very durable and water resistant watch for many of my hobbies (not to mention my career) and because I live in North Idaho which by default means I must deal with hostile weather quite a bit.

    I’ve found that with its inherent water resistance and a tough shroud the Seiko tunas are well suited for a life spent in snow, water and tough outdoors hobbies. I compete in 3 gun competitions, go off-roading, hiking and generally immerse myself in all that North Idaho has to offer. I have yet to see any of my Seiko tunas or even the less expensive divers fail.

    Yes I suppose I could use the Casio Pathfinder or Suuno series of watches but honestly the Seiko’s just have such wonderful style and I prefer a watch that isn’t digital and I really do believe the watch is an exstension of who I am and I’m not a fan of all the digital nonsense.

    When I meet a man the things I look at first are his shoes and his watch. If he’s wearing combat boots or workboots and a Seiko tuna I know thats a man I can work with. Sadly I meet more men who think brightly colored sneakers are men’s footwear and their cellphone is an acceptable time keeper.

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