Seiko's affordable dive watches run in a clear family line, and once you know it the listings start to make sense. The asymmetric 6105 led to the cushion-cased 6309 Turtle. A quartz diver, the 7548, introduced the case shape the SKX007 would later wear, and the date-only 7002 carried it through to the 1990s. All of them turn up on eBay every day. Finding an original one takes more work, because these were cheap, tough watches that people actually dived in, and plenty have since been rebuilt with aftermarket dials, hands and bezels. Here's how they differ and what to look for in each.
The 6105-8110, the Willard
The 6105 series followed Seiko's first professional diver in 1968. The first version had a symmetrical case, and around 1970 Seiko replaced it with the asymmetric 6105-8110, which you'll also see listed as its sibling reference 6105-8119. It's a 44mm, 17-jewel automatic rated to 150m, with 19mm lugs. The lugs are short, so it wears closer to a 40mm watch than the number suggests. Martin Sheen wore one as Captain Willard in Apocalypse Now, and it was sold in military PXs during the Vietnam War.
The crown doesn't screw down. It uses a turn-and-lock design, and an original crown is marked LOCK with a rotating arrow. Fratello's writer found that most 6105s for sale had been altered, from refinished dials and hands to aftermarket bezel inserts. The seconds hand is a quick tell. It ends in a red dot followed by a lume dot, and if those colors look fresher than the rest of the dial, something has been replaced.
The 6309 Turtle
Seiko launched the cushion-cased Turtle in 1976. The 6306 version was made for Japan, with a hacking movement and a Kanji day wheel. The 6309-7040 is the worldwide version and the one most people mean when they say Turtle. The 6309-7049 is the same watch for North America. The case is 45mm wide, 48mm long and 13mm thick, with 22mm lugs, a 150m rating and a screw-down crown at 4 o'clock. Ed Harris wore one through The Abyss. Sources disagree on when production ended, with dates from 1982 to 1988.
The 17-jewel 6309 is automatic, but it doesn't hand-wind or hack. A light shake gets it running. Early dials carry the Suwa symbol just below the depth rating, and later dials drop it and say the case was made in Hong Kong. Fake dials are everywhere. Look for a date window with no bevel, or a 6 o'clock marker that runs down into the small print at the bottom of the dial. Original hands are flat with sharp edges, while aftermarket ones look rounder and more three-dimensional. Ask the seller whether the crown screws down fully, because the crown tube isn't replaceable and a stripped one is close to impossible to fix.
The slimmer 6309-7290 and the quartz 7548
In 1982 Seiko moved the 6309 movement into a slimmer, more angular case, the 6309-7290, which some collectors call the Slim Turtle. That case shape had already appeared in late 1978 on the 7548, a 150m quartz diver about 42mm across. Seiko made the 7548 until 1985 in a long list of variants. Its case is the direct ancestor of the SKX, so it's a good pick if you want that shape on a vintage watch without nursing a mechanical movement. Because it's quartz, ask the seller for a short video of the seconds hand ticking and whether it keeps time on a fresh battery.
The 7002
The 7002 replaced the 6309 in 1988 and ran until 1996. Its 7000-series movement dropped the day display, so a correct 7002 shows the date only, and like the 6309 it can't be wound by hand. Early versions were rated to 150m, and later ones reached 200m after Seiko changed how the crystal was fitted. The case is 41mm wide, 45mm long and 13mm thick, and Fratello's reviewer called it supremely comfortable.
It's also the watch modders have used for decades. Fratello's writer bought three before finding a correct one and reckoned nearly every 7002 on eBay had been modded or fitted with aftermarket parts. Watch for fake dials with the wrong dial code or a font that doesn't match the original. The factory lume often turns gray and a little grainy, so bright green lume is a sign the dial or hands have been changed.
The SKX007 and the new Turtle
The SKX007 arrived in 1996 and kept the 7548's case shape, now at 42.5mm with a 46mm lug-to-lug length. It's a 200m diver on the 7S26 automatic, which can't be hand-wound and doesn't hack. Seiko had stopped supplying it to dealers by 2019. A J at the end of the reference, as in SKX007J, means it was made in Japan, while the others were made elsewhere in Asia. The SKX009 and the smaller SKX013 are its closest siblings.
If you love the Turtle shape and want a watch you can wear hard, look at the SRP777. Seiko brought the Turtle back in 2016 as a Prospex diver, about half a millimeter larger than the 6309 at 45mm, rated to 200m and running the 4R36, which hacks and hand-winds.
Which one to buy
For a first vintage Seiko diver, a 6309 Turtle or a 7002 gives you the most watch for the least risk, provided you check the dial and hands carefully. Pick the 7548 if you want vintage looks with quartz convenience. Buy an SKX007 if you'd rather have a younger watch with easy parts, and pay more for one that hasn't been modded if originality matters to you. Save the 6105 for when you can recognize a correct dial and crown on sight, because it's the most altered of the lot.
What to check in a listing
- Dial and hands. Look at the photos in angled light. The lume on the dial and hands should have aged the same way, and the printing should match known original examples of the exact reference.
- Bezel and crown. Compare the bezel insert with reference photos and ask the seller whether the crown screws or locks down properly.
- Case back. Ask for a clear photo. The reference should match the dial, and the serial number should date the watch inside that model's production years.
- Movement. Ask the seller for a photo of the movement. The caliber should match the case back, and a 6309 or 7002 that hacks or hand-winds has the wrong movement inside.
- Service and water. Ask when it was last serviced. Treat any vintage diver as not water resistant until a watchmaker has fitted new gaskets and pressure tested it.
For the dial and parts tells in more depth, read how to spot a redialed or franken Seiko. To read the case back and date the serial number, see Seiko reference numbers decoded.
