If you know me and my watch taste a bit, then you probably know that I love Seiko dive watches, especially Tunas. Seiko SBBN015 300m quartz Tuna is probably my favorite watch among my whole collection. Recently, I’ve picked another Tuna for my personal watch collection, which is Seiko Solar Tuna SBDN028. This watch is a member of the latest Seiko’s limited edition family. You can check out my unboxing and hands-on review here. Today, I would like to show you guys how this new model compares with his older brother.

The history of Seiko shrouded dive watches goes way back to 1975 when the first Tuna was developed. If you are interested in the Seiko shrouded divers history and their progression, I highly recommend reading this article on thespringbar.com. Juvy presents the most important Tuna models throughout the history and their impact on the professional diving scene.

As you are probably aware, the common characteristic of a Seiko Tuna is its external shroud protecting the watch case and providing shock absorption. Both SBBN015 and SBND028 have this feature; however, the shroud on SBBN015 is made of stainless steel while its younger brother uses a plastic shroud. This fact alone means that the SBDN028 will not be everyone’s cup of tea. Using plastic means the overall weight of the watch is lower but you lose that premium feeling. I really wish Seiko went with steel on the Solar Tuna as well. Granted, SBDN028 is a ~$400 watch, while SBBN015 is at least twice as much but it would benefit so much if they went the extra mile for that premium feel. I can’t stress it enough, I would be willing to pay additional ~$50-100 just the get that stainless steel (or ceramic for that matter) shroud on SBDN Tuna. The plastic looks ok-ish but I believe it will scratch very easily making the whole watch look unattractive. Meanwhile, I’ve owned SBBN015 for 2,5 years now and its stainless steel shroud still looks amazing. Of course, I got a couple of scratches here and there but it’s been holding up relatively well. Perhaps, some modders out there will come up with a 3rd party shroud for SBDN Tunas, it’s been done in the past. However, this lineup being a limited edition, I would not hold my breath for it.

There, I’ve got it out of my system and now we can go to other parts of the watches. Let’s focus on dials and crystals for the moment. Both watches uses proprietary Seiko Hardlex crystals. On SBBN015 we have a beautiful double domed Hardlex, while SBDN028 uses just a slightly domed crystal. It makes sense for the Solar Tuna not to use an extremely domed crystal because the watch tries to keep a low profile of just 12 mm. The other difference between the watch is the dial diameter. SBDN028 being a smaller watch has a smaller dial. Makes sense. However, it’s not just it. The proportions between a bezel and a dial are also different. SBDN has a definitely wider bezel which makes the dial to appear even smaller than it actually is. It also translates to the proportions of the elements on the dials. SBBN015 has large hour indices, while the Solar Tuna has much smaller indices. They are actually so tiny that is also translates to lume performance. SBBN015 having larger indices with more superluminova on them glows stronger and longer in comparison to its younger brother. But do not worry, SBDN028 has nothing to be ashamed of in the lume department, it’s still the same amazing Seiko lume that we all know and love.

When it comes to cases of these two, differences does not stop at the use of different material for the shrouds. SBBN015 is built to be a professional dive watch providing 300 m of water resistance and allowing for saturation diving thanks to special L-shaped gasket. SBDN028, being a Tuna on a budget, is certainly a more casual watch with a water resistance of 200 m. And it’s not suitable for saturation diving. Nevertheless, both are ISO compliant dive watches in their respected depth categories.

In terms of movements there are still significant differences between both watches. SBBN015 uses 7C46 high torque quartz movement. This movement was especially designed for the Tuna line being able to survive in extreme conditions. Being a high torque movement, 7C46 is extremely power efficient, which allows for up 5 years of work on a single battery. On the other hand, SBDN028 uses V147 Solar quartz movement. It’s an entry level Seiko movement but being powered by solar energy means that you don’t have to change the battery at all. It’s really handy feature on a dive watch as you want avoid opening the case to preserve water resistance capabilities.

Both watches wear great on the wrist. The credit goes to the almost lugless design of the cases. Even though cases have 48 and 46 mm respectively, they still wear really well. Furthermore, the larger SBBN015 is a great match for my 7,5 inch wrist while I find SBDN028 to be a bit too small. It does not feel out of place but a couple of millimeters more would be definitely welcome.

I know that this comparison might not be too fair due to price differences between these two watches. However, if you are not a budget and you love the Tuna design as I do, the new Solar Tuna lineup is a good place to start. You get to try what is all about and you don’t have to break a bank. All the traits of a Tuna are here, a shroud, rugged design, vintage vibe. In case of SBDN028 you also get probably the most interesting color scheme of black with gold accents. Speaking of which, my secret dream is Seiko will make a modern 300 m quartz Tuna in black and gold. Heck, even a 1000 m black and gold Tuna would do it. So, is SBDN028 a keeper then? Unfortunately not in my case. Don’t get me wrong, I think it’s a neat little watch and it would definitely please many people. There is a high chance it will become a highly sought after timepiece among watch collectors in future because of being a limited edition watch. However, the simple truth is SBBN015 is easily a superior watch, I would probably not wear SBDN028 much, if at all. I hope it will find a new home really soon and see more wrist time it deserves.

Seiko TUNA SBBN015 Seiko Solar TUNA SBDN028
Measurements 48 mm x 15 mm 46 mm x 12 mm
Case material Stainless Steel Stainless Steel + plastic
Water resistance 300m, suitable for saturation diving 200m
Movement High torque quartz 7C46 Solar V174
Dial Bigger dial and indices Small dial and tiny indices
Band Stainless steel bracelet Silicone strap
Availability Out of production, replaced by SBBN031 Limited edition of 3000 pieces, probably sold out already
Price ~$900 ~$400



About Author

Watch enthusiast who loves to take photos of his watches, blogger, and founder of Lug2Lug.