Seiko Prospex MarineMaster Professional 300m Black Tuna SBBN035 Diver 47mm


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We take trades against any of our watches!!! We also buy watch packages!!

Seiko Tuna is the name given to Seiko’s range of watches designed for scuba and professional diving. In particular, Seiko made these watches with saturation diving or greater depth diving in mind. All of the watches in the Seiko Tuna range are characterized by protective screwed-on shrouds that have earned them the nickname of “Tuna”. 


The Seiko Tuna collection boasts of many firsts. The collection was the first to feature a titanium/stainless steel shroud, a monocoque case, an L-shaped gasket, and a vented rubber strap. Primarily built for functionality, the Seiko Tuna watches can withstand great depths as tools for professional divers.Built in 1975, the first Seiko Tuna watch was created in response to a letter the company received in 1968. A saturation diver from Kure City in the Hiroshima, Japan sent a complaint regarding Seiko divers watches, which the company had been making since 1965. These pre-Tuna models were not robust to impact and could not withstand exposure to deep underwater pressure for prolonged periods.

Seiko engineers took on the challenge to create the “ultimate professional diver’s watch. These engineers, led by Ikuo Tokunaga, decided to develop the new Seiko Tuna watches for saturation diving from the start. Tokunaga and his team began development in 1968 and released the first Seiko Tuna watch seven years later with more than 20 patents.

The Seiko Marine Master Professional 300M Tuna Ref. SBBN035 is powered by Seiko’s iconic high tech quartz movement, 7C46. The 7 jeweled movement with extremely hi-torque tolerances and high efficiency enables the gears and pinions to move and turn the hands in perfect sync to the energy-pulse, with much less kinetic effort via the electronic step motors that power them. Thus making for a highly accurate and efficient full size quartz machine to perform strongly with much less resistance resulting in longer battery life.

The 47mm stainless steel case might sound intimidating at first glance. But because of the “lug-less” design, the case is only 47mm lugs to lugs. That means this “Tuna” sits so comfortably on the wrist. In fact we think it fits more like a conventional 42mm watch with lugs. The stainless steel case and shroud is satin brushed on the sides and polished on the top for an exquisite feel. Thereafter the case and shroud are treated with a Super Hard Black coating to protect it from scratches. The dial’s makers and hands are treated with Seiko’s Lumibrite for awesome low light visibility. Dual-curved Hardlex for added toughness. 

The SBBN033 Tuna comes with a Seiko’s extremely comfortable rubber strap.


BRAND: Seiko

MODEL: MarineMaster Professional 300m – Ref SBBN035

MOVEMENT: Japanese Quartz

CASE: Black Coated Stainless Steel

CROWN: Screw Down 

SIZE: 47mm

LUGS: 22mm

DIAL: Black Dial 

BEZEL: rotating Diver

CONDITION: Pre-owned – As-New! – Factory Warranty until Sept 2022!

BOXES/PAPERS: 100% Complete Set! – comes with everything as shown in pictures!


STRAP/BRACELET: – Original Seiko Black Rubber dive strap with Black Steel buckle.


We buy similar watches…large packages as well as one at a time. We also take trades against any of our watches…

Let us know what you have in your collection!! I consider all watches in trade! Please upload pictures and include details of your trades through my Trade/Buy tab at the top of my homepage.