Seiko 6309 Turtle — the Professional 150 dial

Vintage Seiko 6309 Turtle in hand — photo: Uncommon Artifact

Photo: Uncommon Artifact

Before "Turtle" was a reissue line, it was this: a cushion case, a Calibre 6309, and a dial that just says Professional 150.

Verdict

What it is Vintage Seiko 6309 "Turtle" diver, 1976–1988 — cushion case, day-date, dial signed "Professional 150"
Price Not stated — vintage, priced per example
Availability Secondary market only
The angle The photographed watch is the original article that the modern Prospex Turtle reissues quote.
Verdict Condition decides everything at this age, and the dial and hands are the watch.

The story

Seiko built the 6309-7040 and its regional twin the 7049 from 1976 to 1988 as the successor to the 6105 divers: a broad cushion case with the crown at four o'clock, a screw-down crown, and Calibre 6309 inside — a 17-jewel automatic running at 21,600 bph with a day-date display and no hacking seconds. The rating was 150 metres, printed on the dial. Variants of the family carry different dial text; the photographed example reads "PROFESSIONAL 150" over the six, with the applied indexes and the split marker at twelve that define the type. It is photographed in hand, on a beads-of-rice style bracelet.

The modern Prospex Turtle exists because this formula — size, legibility, a case shape that shrugs off knocks — was already right in 1976. The judgement for an original is narrower than for the reissue: the 6309 market is flooded with aftermarket dials, hands and bezel inserts, so an honest example is worth more than a shiny one. What is being bought at this point is not a dive watch. It is the evidence that the dial, hands and case are the ones the watch left Suwa with.

Specs

Family reference 6309-7040 / 7049 ("Turtle")
Era 1976–1988
Movement Calibre 6309 — automatic, 17 jewels, 21,600 bph, non-hacking, day-date
Case Stainless steel cushion case, approx. 44mm wide × 45mm long × 13.6mm thick
Dial Black, applied indexes, day-date at 3; "Professional 150" variant, as photographed
Bezel Rotating elapsed-time bezel, black insert
Crystal Hardlex mineral
Crown Screw-down, at 4 o'clock
Water resistance 150 metres (period rating, as printed on the dial)
Bracelet Beads-of-rice style bracelet, as photographed

What to check before buying

  • Dial and hands first. Aftermarket replacements are everywhere in this family and usually read too crisp, too even, too new. Original lume ages; reproduction lume performs.
  • The day-date changeover. Both wheels should advance cleanly at midnight. A lazy day wheel is common and fixable, but it is a service cost — price it.
  • Crown and tube threads. The 6309's spring-loaded crown assembly is a known wear point. A crown that won't catch its threads is the expensive sentence in any listing.
  • Do not dive on the dial. "150" is a 1970s rating. Until a watchmaker pressure-tests the watch, treat it as a dry-land instrument.
  • Bezel action. It should turn with even resistance and no grit. A frozen or floppy bezel tells you how the watch was stored.

Want one?

  1. In the shop: browse current stock — one-off pieces, and they turn over fast.
  2. Hunting one? Join the Want List — tell us the maker and the budget; vintage Seiko divers surface in our trawl most weeks.

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Photographed for the daily wrist-shot story series — not our stock, and not a sales listing. Disclosure

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