The 55th Anniversary: Seiko Tuna - SLA037
The Seiko Tuna diver is a vintage release commemorating the 55th anniversary of the original Japanese Dive watch. In 1965 Seiko identified a hole in the watch market. It was producing quality watches that could handle dive depths and make them widely available. The original dive watch was rated for 150m which is only 50m less than what we see with the modern Seiko Tuna. At the time, these new dive watches by Seiko were engineered to be ultra legible and reliable. The original Seiko Tuna was so reliable that it accompanied the Japanese Antarctic Research Expedition from the years 1966 to 1969.
Fast forward 55 years and we see almost a carbon copy of the original with the updated Seiko Tuna SLA037. Literally the only difference is the case design, 1.9mm wider, and an increased depth rating of 200m. The Seiko Tuna has also evolved with modern mechanical technology, incorporating the 10-Beat Caliber 8L55. We’ll go into more detail about the Caliber 8L55 later in this Seiko Tuna Review.
First Impression For Our Seiko Tuna Review
Seiko Tuna Specs
| Caliber | In-House 8L55 |
| Movement Type | High Beat Automatic |
| Accuracy | +15/ -10 Seconds Per Day |
| Power Reserve | 55 Hours |
| Case Material | Ever-Brilliant Steel |
| Band Material | Silicone |
| Crystal | Sapphire |
| Crystal Coating | Anti-Reflective |
| Lume | Lumibrite |
| Water Resistance | 200m |
| Case Size | 39.9 mm |
| Lug to Lug | 47.9 mm |
| Bezel | Unidirectional |
| Functions | Hour / Minute / Second Hands, Date |
Seiko Tuna 8L55 High Beat Movement
The Seiko Tuna is housed with the 8L55 high beat movement. The 8L55 has an impressive 36,000 vph which gives the second hand an almost true sweep. There are not many high beat movements produced today because they are hard to produce at scale economically which makes it all the more impressive Seiko has included it on this Prospex. The Caliber 8L55 is most commonly compared to the Grand Seiko Caliber 9S85 which is also a high beat movement. The common understanding between the two is that the 8L55 is the unfinished version of the GS Caliber 9S85. From what I have been told these movements are actually even made in the same factory side by side.
How Much Is The Seiko Tuna
The MSRP of the 55th anniversary of the Seiko Tuna is $6,300. The price of the Seiko Tuna is completely justified by its quality and heritage. What was a surprise to me was that it wasn’t part of Grand Seiko. It’s no secret that Seiko and Grand Seiko have been increasing the price of their watches, and to be fair the same goes for the quality, but the jump seemed out of place. If you can get past that the Seiko Tuna is not a Grand Seiko, there shouldn’t be anything holding you back from buying this watch. Especially since the Seiko Tuna has been released in limited numbers and is selling at or above MSRP on the pre-owned market. It is showing all the signs of a hot collectors item.
