The Omega Seamaster Planet Ocean 600M Co-Axial (Ref. 2909.50.38) is a professional Swiss diver belonging to the first generation of the Planet Ocean collection, introduced in 2005. This configuration combines a 42 mm stainless steel case with a black dial, the distinctive orange bezel, and a matching alligator strap, creating one of the most visually recognizable interpretations of the original collection.
At its technical core is the automatic Omega 2500 caliber with Co-Axial escapement and COSC chronometer certification. The combination of water resistance to 600 meters, a helium escape valve, and more restrained proportions compared with several later generations makes this Planet Ocean particularly interesting for those looking for an early Omega diver from the Co-Axial era.
Design
The visual identity is built primarily around the contrast between black and orange. The orange bezel immediately dominates the front of the watch and features a black 60-minute scale, with highly visible numerals at ten-minute intervals. The same color returns on the applied Arabic numerals at 6, 9, and 12 o’clock, creating a direct connection between the dial and bezel without compromising the readability of the main indications.
The black dial features the characteristic layout of the early Planet Ocean models. The applied hour markers are large and filled with luminescent material, while the broad hands follow the functional design language of the Seamaster family. The minute hand is immediately distinguishable from the hour hand, a particularly important detail in the layout of a diver. The date window at 3 o’clock replaces the corresponding hour marker and remains relatively discreet within the overall composition.
The peripheral minute track and the numerous inscriptions across the lower half of the dial add information without excessively disrupting the visual hierarchy. The domed crystal also contributes to the character of the Planet Ocean models from this generation.
Another distinctive choice is the original orange alligator strap. Its color directly echoes the bezel and dial numerals, while the rubber inner lining addresses the practical requirements of a strap intended for use with a sports watch. Compared with configurations fitted with a stainless steel bracelet or rubber strap, this solution further emphasizes the distinctive character of the model.
Case & Construction
The case is made of stainless steel and measures 42 mm in diameter, with a lug width of 20 mm. Case thickness is not listed in the consulted Omega documentation; measurements reported by secondary sources generally place it at approximately 14.2–14.5 mm. The lug-to-lug measurement of approximately 48 mm should likewise be considered an approximate figure rather than an official manufacturer specification.
The construction combines brushed and polished surfaces and includes a screw-down winding crown. At 10 o’clock is the characteristic manual helium escape valve, intended primarily for use during saturation diving.
The bezel is unidirectional, as required for measuring dive times. The dial is protected by a domed sapphire crystal, scratch-resistant and treated with an anti-reflective coating. Omega officially rates the model to 60 ATM, equivalent to 600 m / 2,000 ft. In the case of a pre-owned example of this age, actual water resistance should naturally be verified through an appropriate pressure test before the watch is used in water.
Movement
Inside is the Omega Caliber 2500, a Swiss automatic mechanical movement based on the architecture of the ETA 2892 family and extensively modified by Omega to incorporate, among other changes, the Co-Axial escapement. This particular feature makes the caliber especially significant in the brand’s recent history: the 2500 family represented one of the major stages in the widespread adoption of Co-Axial technology across Omega’s production.
The versions of the 2500 relevant to the production of the first Planet Ocean operate at 25,200 vibrations per hour, equivalent to 3.5 Hz, and provide approximately 48 hours of power reserve. The movement uses automatic winding and is chronometer-certified by COSC. Technical specifications for the relevant variants also indicate 27 jewels.
An important consideration for collectors concerns the internal evolution of the caliber. During production of the first-generation Planet Ocean, different revisions were used, including the 2500C and, later, the 2500D. The latter adopted a three-level Co-Axial escapement compared with the earlier two-level configuration. However, it is not correct to automatically assign either version to every example based solely on the reference: to determine which revision is actually installed, it is preferable to inspect the movement directly or rely on trustworthy documentation relating to the individual watch.
Functions & Complications
The indications include hours, minutes, central seconds, and date at 3 o’clock. The date mechanism offers quick adjustment through the crown, allowing the day of the month to be corrected without repeatedly advancing the hands through complete 24-hour cycles.
The date is the movement’s actual complication. The unidirectional bezel with its 60-minute scale and the manual helium escape valve, on the other hand, are functional devices associated with the watch’s diving purpose rather than mechanical complications. This distinction avoids attributing to the caliber functions that actually belong to the construction of the case.
Performance
The 42 mm diameter and reported lug-to-lug measurement of approximately 48 mm suggest a substantial yet relatively controlled wrist presence for a professional diver in this category. The thickness of nearly 14.5 mm remains noticeable and makes the model less than ideal under tighter shirt cuffs. The 20 mm lug width is well proportioned to the 42 mm case and also allows for a wide selection of compatible alternative straps.
Legibility is one of its strengths. The black background, large luminescent hour markers, and broad hands create an immediate separation of information, while the strong color contrast makes it possible to quickly distinguish the main elements of the dial.
The alligator strap with rubber lining makes this configuration more distinctive than versions fitted with a bracelet or rubber strap. For frequent use in water, however, a full rubber strap or stainless steel bracelet represents a more practical solution for a professional diver.
Technical Data
Brand: Omega Watches;
Model: Omega Seamaster Planet Ocean 600M Co-Axial (Ref. 2909.50.38);
Year: 2005;
Case Material: Stainless Steel;
Case Diameter: 42 mm;
Case Thickness: ~14.2 mm (~14.5 mm including the domed crystal);
Lug Width: 20 mm;
Lug-to-Lug: ~48 mm;
Crystal: Domed Scratch-Resistant Sapphire Crystal with Anti-Reflective Treatment;
Water Resistance: 600 m / 2,000 ft (60 ATM);
Power Reserve: ~48 hours;
Movement: Automatic Mechanical Watches – Omega Caliber 2500, Automatic Co-Axial Chronometer (Swiss Movement);
Functions: Hours, Minutes, Central Seconds, Date, Quickset Date, Automatic Winding, Unidirectional 60-Minute Diving Bezel, Helium Escape Valve;
Complications: Date Display;
Bracelet / Strap: Orange Alligator Leather Strap with Rubber Lining and Stainless Steel Folding Clasp;;
Type: Calendar Watches, Diver Watches, Luxury Watches, Sports Watches, Tool Watches;
Sex: Men’s Watches;
Nationality: Swiss Watches.
Retail Price (Launch): ~€2,800 / ~$3,400.
The first Planet Ocean occupies an important position in the modern history of Omega because it brings together three elements that would help define the collection: professional diving performance, Co-Axial technology, and an immediately recognizable aesthetic identity. Orange, in particular, became one of the most distinctive visual signatures of the early Planet Ocean models. The same generation gained further recognition through the 2006 film Casino Royale, in which Daniel Craig wore a Planet Ocean from the same family, although with a different reference.
Among the strengths of this configuration are its relatively balanced proportions compared with some later Planet Ocean models, the COSC-certified 2500 caliber, professional construction, and the strong identity of the black-and-orange combination. As for its compromises, the approximately 48-hour power reserve is modest by the standards of modern Omega calibers, while the alligator strap, despite its rubber lining, remains less suitable for regular underwater use than rubber or stainless steel.
For a pre-owned example, the assessment should therefore not depend solely on its appearance or the generation of its caliber. Case condition, documented servicing, the condition of the bezel and strap, correct movement operation, and above all verification of water resistance are determining factors. In good condition, this Omega Seamaster Planet Ocean 600M Co-Axial remains a particularly representative example of the early phase of Omega’s modern Co-Axial production.
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