Case #756 — Omega Planet Ocean 43.5 Ref. 215.30.44.210.01.001

Case #756 — Omega Seamaster Planet Ocean 600M Co‑Axial Master Chronometer 43.5 mm

Ref. 215.30.44.21.01.001

Status: Available

Condition: Very Good Pre-Owned

Scope: Box and Papers (no warranty card); independent service receipt dated July 2026

Year: Unknown

🔎 Case Notes

Black ceramic dial, black ceramic bezel, steel case, steel bracelet. The Planet Ocean in its purest form — the configuration that most people picture when the model name is spoken, and the one Omega kept in the catalogue longest.

What separates this generation from the Planet Oceans that came before it is what sits behind the dial. Reference 215.30.44.21.01.001 was introduced at Baselworld 2016, powered by the Master Co-Axial calibre 8900 in a 43.5 mm case — a size previously only available in the GMT model. That makes this a Master Chronometer-era Planet Ocean: METAS-certified after the eight tests set by the Swiss Federal Institute of Metrology, guaranteeing precision, performance and magnetic resistance to the Swiss industry's highest standard, with resistance to magnetic fields up to 15,000 gauss.

Omega's own description of the reference is precise about the materials: a black ceramic dial with Arabic numerals and a date window at 3 o'clock, a black ceramic unidirectional bezel with Liquidmetal™ diving scale on a 43.5 mm stainless steel case, an alveol screw-in caseback, and a stainless steel bracelet with patented extendable foldover clasp. This example is on that steel bracelet with its folding clasp, currently sized to fit an approximately 7¾-inch wrist.

BST grades it Very Good Pre-Owned. It is a watch that has been worn and carries the light handling marks consistent with that grade; no specific defects were recorded during inspection, and the case-file photographs should be reviewed as part of the description. It comes with its box and papers. There is no warranty card. It does carry a recent mechanical advantage: an independent (non-Omega) service performed in July 2026, accompanied by the service receipt.

🕰️ The Evidence

• Reference: 215.30.44.21.01.001
• Model / Collection: Omega Seamaster Planet Ocean 600M Co-Axial Master Chronometer 43.5 mm
• Year: Unknown
• Case: Stainless steel (Omega uses 316L stainless steel)
• Case Diameter: 43.5 mm (commonly listed in the market as 44 mm)
• Thickness: 16.09 mm
• Lug-to-Lug: 49.00 mm
• Lug Width: 21 mm
• Dial: Black ceramic with Arabic numerals and date window at 3 o'clock
• Crystal: Domed scratch-resistant sapphire with anti-reflective treatment on both sides
• Bezel: Black ceramic unidirectional diving bezel with OMEGA Liquidmetal™ diving scale
• Crown: Screw-in; helium-escape valve at the 10 o'clock case edge
• Caseback: Alveol screw-in caseback; the calibre 8900 is visible through the transparent caseback
• Movement: Omega Calibre 8900 — self-winding with Co-Axial escapement, free sprung-balance with silicon balance spring, two barrels mounted in series, automatic winding in both directions, time zone function
• Movement Type: Automatic, normal winding (no chronograph)
• Certification: Master Chronometer, approved by METAS, resistant to magnetic fields reaching 15,000 gauss
• Power Reserve: 60 hours; frequency 3.5 Hz
• Functions: Hours, minutes, seconds, date; time zone function allowing the hour hand to be adjusted to different time zones without stopping the watch
• Water Resistance: 60 bar (600 metres / 2000 feet)
• Bracelet: Omega stainless steel bracelet
• Clasp: Patented extendable foldover (deployant) clasp
• Bracelet Fit: Approximately 7¾-inch wrist
• Condition: Very Good Pre-Owned
• Service: Independent (non-Omega) service, July 2026, with receipt
• Factory Warranty: None — no warranty card present
• Included: Box and Papers; July 2026 independent service receipt

🌟 Collector Provenance

Omega launched the Planet Ocean line in 2005 with its maritime legacy in mind, and the Planet Ocean 600M Master Chronometer carries that dive-watch heritage forward. In two decades the model has become Omega's serious diver — the one that sits above the Diver 300M in depth rating, case presence and, in this generation, movement specification.

The 43.5 mm case is the pivot point of this reference's story. When the 8900-powered version arrived in 2016, the 43.5 mm diameter was carried over from a size previously reserved for the GMT model — Omega effectively rationalising the line around a single large-diameter case rather than the 42 mm and 45.5 mm pairing that collectors associate with the earlier 8500-era watches. Buyers who want a Planet Ocean with genuine wrist authority, rather than a scaled-down interpretation, tend to look for exactly this size.

The dial and bezel matter too, and they are frequently misread. This is not a lacquered dial: the dial itself is black ceramic, matched to a black ceramic bezel whose diving scale is executed in Liquidmetal™. The result is a surface with a depth and a resistance to ageing that painted dials of earlier generations cannot claim, and a bezel scale bonded into the ceramic rather than printed on top of it.

Black-on-black steel-on-steel remains the reference point of the collection. It is the least theatrical of the Planet Ocean variants — no orange bezel, no white ceramic, no titanium — and for a great many collectors it is the one that stays in the box the longest and gets worn the most.

🌟 Technical Provenance

Calibre 8900 is the watch's strongest technical argument. It is the first of a redesigned family of automatic Co-Axial movements from Omega, launched at Baselworld in 2015 as the successor to the 8500 family introduced in 2007. Two barrels in series give a 60-hour power reserve, a free-sprung balance with silicon balance spring provides resistance to magnetic fields up to 15,000 gauss, and the movement operates at 25,200 A/h rather than the more common 28,800 A/h.

The METAS certification is what gives the Master Chronometer designation its weight. Omega's Master Chronometer watches are tested twice, a process the brand frames as delivering precision beyond that of a conventionally certified chronometer. In practical terms, magnetism — the single most common cause of a mechanical watch suddenly running badly — is effectively removed as a variable.

The 8900's other signature is its handling. It does not have a quickset date, but it does have an independently adjustable hour hand, the so-called "Time Zone Function", which allows the wearer to reset the time when travelling without a GMT hand, and to move the date forwards and backwards using the same mechanism. The hour hand is adjusted without stopping the watch — the minute and seconds hands keep running, so a time-zone change costs no accuracy at all. Owners who travel regularly tend to regard this as the defining advantage of the 8900 over the single-barrel 8800.

🧾 From the Case File

This is a large watch and should be understood as one. At 43.5 mm across, 16.09 mm thick and 49.00 mm lug-to-lug, it wears with real presence; the relatively contained lug-to-lug length keeps it from overhanging a medium wrist, but the thickness is genuine and the watch sits tall under a shirt cuff. On the steel bracelet the complete watch weighs roughly 216 g, and that mass is part of the appeal for buyers who want a tool diver that announces itself.

It is currently sized for an approximately 7¾-inch wrist, and the patented extendable foldover clasp allows on-the-wrist micro-adjustment for the day-to-day swelling that every owner of a heavy steel bracelet eventually notices. The 21 mm lug width is worth knowing in advance if strap-swapping is part of the plan — it is an unusual size, and Omega's own rubber and leather options are the easiest route.

For real-world use, the specification is close to over-engineered: 600 metres of water resistance with a helium-escape valve, a ceramic bezel and ceramic dial that resist the marks a steel diver collects over years, and a movement certified against the magnetic fields that surround laptops, phone cases and speakers every day. Sixty hours of reserve means a watch taken off on Friday evening is still running on Monday morning.

The service history is the practical advantage here. A July 2026 service by an independent watchmaker, documented by its receipt, means the buyer is not inheriting an unknown maintenance interval on an 8900 — though BST has not conducted timing tests, and no claim about current rate or amplitude is made. The scope is box and papers; there is no warranty card, so this watch is offered outside any Omega factory warranty coverage.

Buy with Confidence

BST guarantees the authenticity of every watch we sell and provides a 30-day mechanical performance guarantee under normal use.

Accuracy may vary with age and service history, and water resistance is not guaranteed unless specifically stated and pressure-tested.

🗝️ BST Verdict

The canonical Planet Ocean: black ceramic dial, black ceramic bezel, steel on steel, in the 43.5 mm case that defined the Master Chronometer generation. Nothing about it is decorative — it is the version collectors keep coming back to precisely because it is the least decorated.

Underneath is the argument that really matters: calibre 8900, twin barrels, 60 hours, silicon hairspring, 15,000 gauss, backed by a time zone function that makes it a quiet travel watch as well as a dive watch. With a documented July 2026 independent service and its box and papers, this is a worn-and-honest example of a reference that is no longer in production, offered with its history stated plainly rather than polished away.

👉 Every case deserves a closer look.