Case #782 — Omega Seamaster Diver 300M (Black Dial, Steel Bracelet) Ref. 210.30.42.20.01.001

Case #782 — Omega Seamaster Diver 300M "Black Wave"

Ref. 210.30.42.20.01.001

Status: Available

Condition: Very Good Pre-Owned

Scope: Box, Papers, and Cards

Year: 2023

🔎 Case Notes

The black-on-black Seamaster Diver 300M is the version most people picture when they hear the name, and it earns that status honestly. The dial here is not printed or stamped but polished black ceramic, laser-engraved with the wave pattern that has identified the Seamaster since the mid-1990s, framed by a unidirectional black ceramic bezel with a white enamel diving scale. In daylight it reads as a glossy, almost lacquered black; in a dive-light angle the waves emerge and the watch stops looking like a generic steel diver.

Inside is the Co-Axial Master Chronometer Calibre 8800, a self-winding movement certified by METAS and resistant to magnetic fields of 15,000 gauss, with a free-sprung balance and silicon balance spring — visible through the sapphire caseback. Water resistance is 300 metres, with the Diver 300M's conically redesigned helium escape valve.

BST grades this example Very Good Pre-Owned. It has clearly been worn and cared for: only hints of minor wear are present on the case sides, bracelet and clasp, with no distracting damage across the dial, bezel or crystal. The year of manufacture is unknown and is not stated here. It arrives on its steel bracelet, sized to fit an approximately 7¾-inch wrist, and is accompanied by Box, Papers, and Cards.

🕰️ The Evidence

• Reference: 210.30.42.20.01.001
• Model / Collection: Omega Seamaster Diver 300M, 42 mm, steel on steel
• Year: Unknown
• Case: Stainless steel, brushed and polished
• Case Diameter: 42 mm
• Thickness: 13.56 mm
• Lug-to-Lug: 49.90 mm
• Lug Width: 20 mm
• Dial: Polished black ceramic with laser-engraved waves and date window at 6 o'clock; rhodium-plated skeleton hands and raised indexes filled with white Super-LumiNova
• Crystal: Domed scratch-resistant sapphire with anti-reflective treatment on both sides
• Bezel: Unidirectional black ceramic with white enamel diving scale
• Crown: Screw-in
• Caseback: Transparent (sapphire)
• Movement: Omega Calibre 8800
• Movement Type: Self-winding with Co-Axial escapement
• Certification: Master Chronometer, approved by METAS; resistant to magnetic fields reaching 15,000 gauss
• Power Reserve: 55 hours
• Frequency: 3.5 Hz
• Functions: Hours, minutes, seconds, date; helium escape valve, unidirectional rotating bezel
• Water Resistance: 30 bar (300 metres / 1000 feet)
• Bracelet: Stainless steel Seamaster Diver 300M bracelet, brushed and polished
• Clasp: Foldover clasp with comfort setting and diver extension
• Bracelet Fit: Approximately 7¾-inch wrist
• Condition: Very Good Pre-Owned — only hints of minor wear on the case sides, bracelet and clasp
• Included: Box, Papers, and Cards

🌟 Collector Provenance

The Diver 300M line dates to 1993, and the modern 42 mm generation represented by this reference arrived as a comprehensive redesign of that lineage. The reference was launched in 2018, the year Omega rebuilt the watch around a slightly larger case, ceramic dial and bezel, a conical helium escape valve and a sapphire caseback — the first time the Seamaster Professional's working movement was made visible as standard.

What collectors tend to fixate on is the dial. Earlier Seamaster 300M generations carried the wave motif as a stamped or printed pattern on metal; this generation renders it in polished black ceramic with laser-engraved waves, which changes the way the dial behaves under light entirely. It is the single detail that most quickly separates a post-2018 example from its predecessors at arm's length, alongside the date's move to 6 o'clock.

The movement is the other dividing line. Where earlier 300M generations used the Calibre 2500 family, this generation standardised on the Co-Axial Master Chronometer Calibre 8800, METAS-approved and rated to 15,000 gauss — an anti-magnetic specification that is still unusual at this level of the market and one of the clearest practical arguments for the modern reference over its ancestors.

Within the generation itself, the black dial on steel bracelet is the anchor configuration rather than a scarce one. That is not a weakness: it is the version that has defined the model's identity, and the one most likely to remain in production memory long after seasonal colourways have come and gone.

🌟 Technical Provenance

The Diver 300M has always been a genuine ISO-style dive instrument rather than a dress watch in diver's clothing, and the specification sheet reflects that. Water resistance is 30 bar, with a screw-in crown, unidirectional rotating bezel and helium escape valve — the valve a decompression system that allows helium to escape from inside the watch during saturation work in pressure chambers.

The Master Chronometer standard is where the modern watch genuinely separates itself from the diving watches of the 1990s. METAS certification tests the cased-up watch, not just the movement, and the Calibre 8800's free-sprung balance with silicon balance spring underpins the 15,000-gauss magnetic resistance claim. In ordinary life that matters less for diving than for the magnets in laptop lids, phone cases, tablet covers and cabinet closures that quietly ruin the timekeeping of conventional watches.

The 55-hour power reserve is the quiet companion to that: take the watch off on Friday evening and, in practical terms, it is still running when you pick it up on Sunday.

🧾 From the Case File

At 42 mm across with a 49.90 mm lug-to-lug and 13.56 mm of thickness, this is a proper full-size sports watch, but the lug geometry is restrained enough that it does not overhang a medium wrist. It is currently sized for an approximately 7¾-inch wrist, which makes it an easy fit for a larger wrist straight out of the box and a straightforward removal of links for anything smaller.

The foldover clasp includes a comfort setting and a diver extension, which in daily use is more valuable than it sounds — the comfort adjustment absorbs the wrist swelling that turns a perfectly sized bracelet into an uncomfortable one by late afternoon, without tools.

The practical case for a pre-owned example in this condition is straightforward. The watch shows only hints of minor wear on the case sides, bracelet and clasp — the sort of light contact any worn steel sports watch accumulates — while remaining a current-generation reference with the ceramic dial, ceramic bezel, sapphire caseback and Master Chronometer movement intact. Buying at this grade means the first light scratch is already behind you rather than ahead of you.

Completeness also matters here. It arrives as Box, Papers, and Cards, which is the configuration most buyers eventually want and the hardest to reassemble after the fact. Note that the year of manufacture is unknown; Omega's standard warranty on this reference is five years, but without a confirmed warranty-card activation date BST makes no claim as to whether any factory warranty period remains.

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 black-dial, black-bezel Diver 300M on steel is the Seamaster at its most legible and most recognisable — a ceramic-dialled, 300-metre, METAS-certified diver that reads as formal enough for a cuff and robust enough to ignore.

This example is honest: worn, well kept, graded Very Good Pre-Owned, with only hints of minor wear on the case sides, bracelet and clasp, sized for an approximately 7¾-inch wrist and complete with Box, Papers, and Cards.

👉 Every case deserves a closer look.