Tuna

The Seiko Tuna has earned cult status thanks to its purpose-built origins as a professional saturation diver’s tool, first released in the 1970s for commercial divers facing depths that destroyed lesser watches. Its monocoque titanium case, distinctive shroud, and sheer 48mm presence set it apart from typical dive watches, making it a conversation piece on and off the wrist. The “Tuna” nickname comes from its can-like shape, and over decades, Seiko has refined the design while keeping its core DNA intact.

Reference numbers matter here: the classic 6159-7010 is the original automatic from 1975, while quartz variants like the 7549-7009 introduced high-accuracy and reliability in the late ‘70s. More recent models, such as the SBBN031 (“Ninja Tuna”) and SBBN033, use the bulletproof quartz 7C46 movement, prized for its long battery life and reliability. Case materials range from stainless steel to titanium, and water resistance varies between 300m and 1000m depending on the reference, directly impacting collectability and price.

Desirability hinges on condition, completeness (box, papers, original rubber strap), and era. Early models and limited editions command premiums, especially those with unpolished cases and original shrouds. Later quartz Tunas are more accessible but still highly sought after for daily wear, thanks to their comfort despite the size. When shopping, consider whether you want a vintage automatic, a quartz “Golden Tuna,” or a modern reissue; each has its own following and value curve.