What’s so special

The Seiko 6309-7040, commonly known as the “Turtle,” is a vintage automatic day/date dive watch that has earned a cult following among collectors and enthusiasts. Produced by Seiko as part of its recreational diver lineup from 1976 through 1988, the Turtle gets its nickname from its distinctive cushion-shaped case, which resembles the shell of a turtle. The 6309-7040 designation was produced for the Japanese and worldwide markets, while its 6309-7049 sibling was built to the same spec for North America.

Measuring 45mm wide, the case wears comfortably despite its size, with circular brushing on top, polished sides, and a screw-down crown positioned at 4 o’clock for improved water resistance and ergonomics. The dial is simple and legible, with large luminescent markers and hands for low-light readability, and day/date complications displayed at 3 o’clock. The bidirectional bezel uses double-row knurling for grip when wet, and the watch carries a 150m water resistance rating. Power comes from the in-house Seiko Caliber 6309 automatic movement, a 17-jewel workhorse known for its reliability and ease of servicing — the Turtle remains one of Seiko’s best-selling and most iconic divers to date.

About this example

This 6309-7040 Turtle comes on a black canvas strap and features a fully intact black dial and black bezel insert with no fading, a nice departure from the “ghost” bezels commonly seen on examples this age. The watch is freshly serviced by us featuring a full movement service and new gaskets. The day/date wheel alternates between English and Spanish (shown here as JUE/27), typical of Seiko’s dual-language calendar wheels from this era. The caseback is stamped 6309-7040 with serial 030241, dating production to March 1980. Case lines are crisp and the automatic movement is winding and running well. As with all vintage pieces, expect honest wear consistent with age — overall this is a good to excellent preowned example of one of Seiko’s most iconic dive watches.