Model guide · Seamaster

Omega Seamaster 120: vintage references, calibres and value

The Seamaster 120 is Omega's 120-metre Seamaster, first listed in 1966. Over the next decade it came hand-wound, automatic, as a chronograph and in a ladies' size, and the reference inside the back tells you which one you have. Every reference on this page is from Omega's own vintage database.

What a Seamaster 120 is

The number is the depth rating: 12 bar, 120 metres, with a screw-in caseback. That puts it between the everyday Seamasters and the Seamaster 300 dive watch; the deepest of the vintage line was the 600-metre Ploprof. It is a Seamaster first, so it shares its movements with the rest of the line, and the Seamaster guide covers those calibres in detail. From 1980 Omega used the 120 name again on quartz divers (the Calypso, the Polaris and the "Plongeur de Luxe"), which are a different watch and a different market.

Every vintage Seamaster 120 reference

The reference is stamped inside the caseback. Omega's database writes it with four digits after the dot, so a 166.0027 is the same watch you will see listed as 166.027.

Source: Omega's vintage database, as held in the reference lookup. ST is stainless steel. A reference not on this list may still be right. Send it and I'll check it.

The calibres inside

The calibre number is on the movement, with the caseback off. The 552, 562 and 565 are the classic 1960s Seamaster automatics, 27.90 mm across; the 552 and 565 have 24 jewels, and the 562 and 565 add the date. The 601 family is the hand-wound equivalent, the 1002 and 1010 are the 1970s automatics with instant date change, and the 1040 is Omega's automatic chronograph of the early 1970s. Full specifications are in the calibre lookup and the Seamaster calibre table.

Dating one

The serial is engraved on the movement; the serial number lookup gives the year band. It should land in or after the year the reference appears in the table above. A 1960s reference with a 1970s serial has had its movement changed.

Parts for the 565 and the rest of the 55x/56x family: the 565 parts list gives the parts people hunt and which calibres share them.

What it's worth

A correct 1960s automatic with its original dial sells in the same band as other Seamasters of the period: high hundreds to low thousands of dollars. The 176.0004 chronograph and the 166.0073 cushion case sell on their own markets, so check the "What they sold for" links above rather than asking prices. A redialed or married example falls toward parts value. What's my Omega worth? explains all three values.

What goes wrong with them

The same three faults as any vintage Seamaster, and all three hide from a listing photo. Redials: repainted dials with print that is too thick or a "120" in the wrong place. Marriages: a movement from a different reference, which the first-three-digits rule above catches. Water: a screw-in back was made to keep water out fifty years ago, not today. Treat any vintage 120 as not water-resistant until the case has been pressure-tested, and look for rust on the dial edge and the movement.

Buying one without getting burned

Before you pay, ask for these photos:

• The dial, square on and in daylight. Look for even print and matching lume on the dial and hands.
• The inside of the caseback. The reference, to check against the table above.
• The movement, with the calibre number readable. It has to match the reference.
• The dial edge and the movement plate, close up. Rust or staining means water got in.
• The lugs from the side. Sharp edges, not polished round.

Questions people ask

When was the Omega Seamaster 120 made?

Omega's vintage database lists the first Seamaster 120 references in 1966, and mechanical 120s run through the 1970s. From 1980 the name went on quartz divers such as the Calypso and Polaris, which are a separate market.

What movement is in a vintage Seamaster 120?

It depends on the reference: 552 in the 165.0027, 562 or 565 in the 166.0027, 601 or 611/613 in the hand-wound 135.0027 and 136.0027, 1002 in the 166.0088, 1010 in the 166.0250, 1040 in the 176.0004 chronograph, and 681 in the ladies' 566 references. The calibre number is stamped on the movement.

Is the Seamaster 120 a dive watch?

It was made for water: most references are rated to 12 bar, 120 metres, with a screw-in caseback. A few, including the 135.0027 and the ladies' 566 references, are listed at 6 bar, 60 metres. After fifty years none of them should be trusted in water until the case has been pressure-tested.

How much is a vintage Seamaster 120 worth?

A correct 1960s automatic with its original dial sells in the same band as other Seamasters of the period, high hundreds to low thousands of US dollars. The chronograph and the 1970s cushion case sell on their own markets, so check the sold prices above. Redialed or married examples fall toward parts value.

Watch Breaker is an independent identification specialist and parts dealer and is not affiliated with, endorsed by or connected to Omega SA or the Swatch Group. Omega is a trademark of Omega SA. Reference data is from Omega's vintage database; specifications are transcribed from printed catalogues. Terms.