Omega 321

Last updated: August 4, 2025
Close-up view of a vintage Omega watch movement with exposed gears, levers, and intricate mechanical parts.

Brand

Caliber Number

321

Production Period

1957-1968; 2019-Present

Lignes

12”’

Diameter

27.0 mm

Height

6.74 mm

Power Reserve

Unconfirmed

Frequency

18,000 bph (2.5 Hz)

Jewels

17

Escapement

Swiss Lever Escapement

Anti-Shock Device

Incabloc

Hand Count

6

Manufacture Region

Unconfirmed

Functions

Manual Winding, Column-Wheel Chronograph (12-hr, 30-min), Small Seconds

Omega 321 Description

The Omega 321 is a legendary, manually wound chronograph movement, famous for being the caliber in the Speedmaster watches worn on the Moon. Based on the Lemania 2310, it uses a sophisticated column-wheel and lateral clutch system. Prized for its beauty and historical significance, the original was made from 1957-1968. In 2019, Omega faithfully re-introduced the caliber into production.

Watches Using The Omega 321 Caliber

A stainless steel Omega Speedmaster 145.012 Professional wristwatch with a black dial, three subdials, tachymeter bezel, and metal link bracelet, shown against a plain light background.
Speedmaster

Omega Speedmaster 145.012

1967-1969
42mm
A vintage Omega Speedmaster CK2998 wristwatch with a black dial, three subdials, silver hour markers, and a stainless steel bracelet, photographed on a plain white background.
Speedmaster

Omega Speedmaster CK2998

1959-1963
39mm
A vintage Omega Speedmaster 2915 wristwatch with a black dial, three subdials, silver hour markers, and a tachymeter scale on the bezel, shown with a black textured strap.
Speedmaster

Omega Speedmaster 2915

1957-1959
38.5mm
A silver Omega Seamaster 145.005 chronograph wristwatch with a white dial, three subdials, and a brown leather strap, displayed against a plain white background.
Seamaster

Omega Seamaster 145.005

1967-1969
35mm
An Omega Speedmaster 105.002 wristwatch with a stainless steel band, black dial, three subdials, white hour and minute hands, and a tachymeter scale on the bezel.
Speedmaster

Omega Speedmaster 105.002

1962-1964
38.5mm
A close-up of an Omega Speedmaster Professional wristwatch with a black dial, chronograph subdials, silver case, and tan leather strap, photographed against a plain white background.
Speedmaster

Omega Speedmaster 105.012

1963-1968
42mm