SEIKO STORY: SEIKO SUMO - What Makes This Watch So Unique

There is absolutely no doubt that Seiko is one of the most prominent brands in the watch industry with its standout timepieces. This global giant is renowned for creating exquisite designs making them a popular choice among adventurers, professionals, collectors, aficionados, and everyone in between.

One of the best and most powerful timepieces they created is the original Seiko Sumo in 2007 which is under their Prospex series. Let us take a look at what sets Seiko Sumo apart from other dive watches today.

SBDC001, the first generation of Seiko SUMO (SOURCE: Shiro Ang Yeong Hui)


Brief History of Seiko Sumo

Seiko has been creating watches since 1965 and their first-ever dive watch left a strong impact in the watch industry.

After Seiko’s engineers received a letter from a professional diver who stated that saturation divers who reach 350 meters deep got all their watches damaged due to stresses and strains, it laid the groundwork for them to accept the challenge and step up their game along with extensive and long years of research and development. 


In 2007, Seiko Sumo was introduced as the youngest diving watch which many enthusiasts dearly loved. It became one of the best-selling Seiko diving watches with its unique and incomparable features. The models under the series were the first diver watches to house the 6R15 automatic caliber which was produced entirely in-house.

SBDC027, The most elegant SEIKO SUMO

The recent third-generation release of Seiko Sumo is now powered by Seiko’s latest 6R35 in-house automatic caliber with an astounding 70-hour power reserve.

 SEIKO 6R35 in-house automatic caliber has 70-hour power reserve. 


Pros of Seiko Sumo

As one of the most coveted diving watches in the world, Seiko Sumo boasts high-quality workmanship, affordability, 200-meter water resistance, and robust automatic in-house mechanism.

In terms of design, it is beefy and chunky. It has a matte black aluminum bezel insert that perfectly matches the black non-reflector dial.

The case is defined and its bulkiness stands out with the soft edges. It is made from high-quality stainless steel that stretches 45mm across and 53mm from lug to lug. 

Like most Seiko diver watches, it also has large rhomboid markers in place and features Lumibrite.

One of the reasons to love Seiko Sumo is that there are so many model options to choose from their recent third generation. You can find the right model to fit your needs and personality.  

"Crafter Blue has recently taken the initiative to collaborate with a local diving group located at Hawaii Islands. The objective of this collaboration is to support several free divers who are part of the diver group in filming the most beautiful underwater creatures all around the world." 

(SOURCE: monochrome)


Cons of Seiko Sumo

There is not much to nitpick about Seiko Sumo, but many find the bezel grip a bit stiff, but everything lines up neatly.

It also features a classic clasp buckle, but if you are not quite a fan of that, you can get a premium quality, pure vulcanized rubber strap by Crafter Blue.


"Seiko rubber watch bands from Crafter Blue are made from vulcanized rubber. Vulcanized rubber is the number one choice for divers and athletes. Through extra processing, the rubber goes through increased fortification. This protects the watch band from harsh elements, such as sun, wind, rain and seawater. The colors of the Crafter Blue watch straps never fade or dull. Colors stay bright in and out of the water."

SPB177, one of my favourite Seiko SUMO


Model Numbers | First to Third Generation 

The three generations of Seiko Sumo garnered so much attention with their alluring design, impeccable functionality, and sophisticated tone. Several innovations are introduced to the third generation such as the 6R35 caliber, the sapphires, and the upgraded power reserve.


Here are the models you can choose from.


SBDC001 (Black Sumo)

SBDC003 (Blue Sumo, also known as “Blumo”) 

SBDC005 (Orange Sumo)

SBDC017 (Yellow Sumo)

SBDC019 (Green Sumo)

SPB029 (Gray Sumo)

SPB031 (50th Anniversary Sumo)


SBDC031 (Black Sumo 2nd Gen)

SBDC033 (Blumo 2nd Gen)

SBDC049 (PADI Sumo)

SBDC057 (Pepsi Sumo)

SBDC069 (Sumo Blue Coral)

SZSC004 (Sumo Green)

SPB055 (Thanos Zimbe Sumo)



SBDC083 - SPB101 (Black Sumo 3rd Gen)

SBDC081 - SPB103 (Green Sunburst Sumo)

SBDC095 - SPB125 (Sumo Black Ninja)

SBDC097 (Gray Sumo 3rd Gen)

SBDC099 (Deep Blue Sumo)

SPB192 (Sumo Thong Sia - Hawksbill Turtle)

SPB194 (Zimbe No. 15 Sumo)

SPB195 (Ion Green Sumo)

SBDC113 (Japan Blue Sumo)

SBDC114 (Sumo Ginza Limited)

SBDC121 (PADI Pepsi Sumo)

SPB175 (Sumo Ice Diver Gray)

SPB177 (Sumo Ice Diver Green)

SPB179 (Sumo Ice Diver Blue)