Seiko Tuna

In 1968, Seiko received a letter from a professional diver complaining about how most diving watches couldn’t withstand the rigours of saturation diving. It took them seven years to come up with a response and in 1975 they built what is widely regarded as the most extreme diving watch every built, the Seiko Marine Master Professional (ref. 6159-7010). Back in ’75, there was nothing else like it out there –, a monocoque titanium case with a unique L-shaped gasket that made the watch impervious to helium gas, an accordion-style rubber strap, a protective outer shell that gave it that distinct tuna-can like look. Watch aficionados referred to this watch as the Tuna and the name stuck.

Seiko Sumo SBDC001 and the original Tuna

Seiko Sumo

The Seiko Prospex Scuba Dive Watch is known as the Sumo. First released in 2007, it comes in three variants – SBDC003 (blue dial with metal bracelet), SBDC001 (black dial and metal bracelet) and the SBDC005 (orange dial with rubber strap). Sturdily built with an aluminum bezel, the watch runs the Caliber 6R15 movement and has a 50-hour power reserve thanks to the use of Seiko’s proprietary Spron alloy mainspring and is rated anti-magnetic.

Seiko Sea Urchin 

The SNZF series from Seiko 5 is an affordable sports watch range that comes in a clutch of sporty dial and bezel variations. Although it’s not quite clear why enthusiasts refer to it as the Sea Urchin, it could be because of the longish minute markings on the dial that resemble the spines of the aquatic animal. The SNZF17K1 model is quite popular with those looking for an affordable Submariner homage watch.

Seiko Monster SKX779 and Sea Urchin

Seiko Monster

Launched in 2000 as an extension of their SKX diving watches range, the Seiko SKX779 and SKX789 soon become extremely popular with those looking for an affordable tool watch. With its distinct look – a toothy bezel, large indices with bright lume, a bezel guard – and bold styling and tough build quality, this watch was soon labelled ‘Monster’ on chat forums and the Orange Monster (SKX789) is probably one of the most distinct divers out there today. The original ran Seiko’s trusty 7S26 movement but in 2015, Seiko updated the Monster with a 4R36 movement and then a further update with a Prospex version (Ref: SBDC023) with a Caliber 6R15 movement.

Seiko Turtle

Seiko introduced the 6309 in 1977 to add to its existing line of divers watch. With its cushion case that resembled a turtle, this watch was fairly popular with diving enthusiasts who favored its reliability and rugged construction.  In 2016, Seiko reintroduced the Turtle with the introduction of the Prospex SRP77x  collection) to much fanfare and now the model is available in four variations.

The Turtle SRP775 and Samurai SRPB09

Seiko Samurai

The Seiko Samurai was first produced from 2004 to 2008. It was called the Samurai by enthusiasts because of the sword-shaped hands on the original. They were made in steel, but a titanium version (Ref. SBDA003) was quite popular with Seikophiles. It ran Seiko's 7s35 movement and was regarded as a tough, no-nonsense diver before production ceased in 2008. This February, Seiko revived the Samurai with the introduction of a limited edition Blue Lagoon Ref. SRPB09. The new Samurai runs Caliber 4R35 and is priced at $550.