Omega
Seamaster Planet Ocean Co-Axial 45.5
232.30.46.21.01.001
A full-size diver built around Omega's landmark in-house Co-Axial movement.
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Overview
The Seamaster Planet Ocean Co-Axial 45.5 mm (ref. 232.30.46.21.01.001) is a large-format professional diver produced by Omega between 2011 and 2016. Its 45.5 mm stainless steel case houses the Calibre 8500, one of the first movements developed entirely in-house by Omega to feature the Co-Axial escapement. The black dial and robust proportions place it firmly in the tradition of serious tool watches within the long-running Seamaster line.
History
The Planet Ocean sub-line was introduced in the mid-2000s as Omega's answer to the demand for a larger, more technically ambitious diver than the classic Seamaster 300M. The 45.5 mm case size represented the upper end of the Planet Ocean range during its production window, appealing to collectors who favoured bold wrist presence. Calibre 8500, introduced around 2007, marked a pivotal moment for Omega as it demonstrated the brand's commitment to fully proprietary movement architecture, including the Co-Axial escapement licensed from George Daniels. This reference remained in production through the mid-2010s before the Planet Ocean collection was updated with successor calibres and revised case designs.
Notable points
- 45.5 mm stainless steel case offers substantial wrist presence while retaining the tool-watch ethos of the Planet Ocean line.
- Calibre 8500 was among the first movements designed and manufactured entirely within Omega, featuring a free-sprung balance and Co-Axial escapement for reduced friction and extended service intervals.
- The Co-Axial escapement, originally conceived by independent watchmaker George Daniels, was adopted by Omega and became a defining technical signature of the brand.
- Black dial with applied indices and a unidirectional rotating bezel underline the reference's credentials as a functional diver.
- Produced from 2011 to 2016, the reference occupies a distinct chapter in Planet Ocean history before the introduction of the Master Chronometer-certified generation.
Specifications
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