OMEGA · Seamaster Diver 300M and Seamaster 300
OMEGA 210.30.42.20.01.001 vs OMEGA 234.30.41.21.03.002
13 published specifications differ between these two, and 1 are identical. Every figure below is what the manufacturer states for that reference; nothing is inferred from the other watch.
What differs
| Specification | OMEGA Seamaster Diver 300M 42mm, black dial210.30.42.20.01.001 | OMEGA Seamaster 300 Co-Axial Master Chronometer 41mm, blue dial234.30.41.21.03.002 |
|---|---|---|
| Case | Steel, 42 mm | Steel, 41 mm |
| Diameter | 42 mm | 41 mm |
| Thickness | 13.56 mm | 13.85 mm |
| Lug to lug | 49.9 mm | 48 mm |
| Lug width | 20 mm | 21 mm |
| Water resistance | 30 bar (300 metres / 1,000 feet) | 30 bar (300 metres / 1000 feet) |
| Crystal | Domed scratch-resistant sapphire crystal with anti-reflective treatment on both sides | Domed, scratch-resistant sapphire crystal with anti-reflective treatment inside |
| Dial | Black | Blue |
| Clasp | Foldover clasp with comfort setting and diver extension | Foldover clasp with comfort setting |
| Calibre | Calibre OMEGA 8800 | Omega 8912 |
| Movement | Self-winding movement with Co-Axial escapement, automatic winding in both directions | Self winding |
| Power reserve | 55 hours | 60 hours |
| Movement notes | Resistant to magnetic fields reaching 15,000 gauss. Free sprung-balance with silicon balance spring. Rhodium plated finish with Geneva waves in arabesque. Total product weight approximately 194 g. | Listed by OMEGA as a Master Chronometer certified watch. Total product weight approximately 156 g. |
What is identical
Worth knowing as much as the differences: these are the specifications you cannot use to tell the two apart.
- Bracelet
- Steel
Stated for one, not the other
These rows cannot be compared, because one maker publishes the figure and the other does not. An empty cell is a gap in the manufacturer's documentation, not a gap in the watch — and not a licence to fill it in from the other column.
| Frequency | 3.5 Hz | not stated |
|---|---|---|
| Certification | Master Chronometer, approved by METAS | not stated |
What the differences cost you
Each note below follows from the published figures in the tables above — what they mean for intake, for a listing, and for the handover. Nothing here estimates a price or a margin.
One of these is the harder fit
Lug to lug is 49.9 mm on the 210.30.42.20.01.001 against 48 mm on the 234.30.41.21.03.002 — a 1.9 mm difference across the wrist. Diameter is what buyers ask about; lug to lug is what decides whether a case sits flat or overhangs. Ask for a wrist measurement before shipping the 210.30.42.20.01.001, and put the figure in the listing rather than the diameter alone.
Different movements to verify and to service
The 210.30.42.20.01.001 runs the Calibre OMEGA 8800 and the 234.30.41.21.03.002 the Omega 8912. Two consequences at intake: the service history that is normal for one calibre is not evidence about the other, and the calibre is the check that catches a movement swapped into the wrong case. Confirm the movement matches the reference rather than assuming it from the dial.
What to check on each
210.30.42.20.01.001
- Confirm the calibre is the 8800 and not the 8900 used in the Aqua Terra. They are different movements with different reserves, and the 8800 has no time zone function to demonstrate.
- Check the crown screws down properly. At 300 metres this is a genuine dive rating and the crown is a primary seal, so any binding or reluctance to seat matters.
- Look at the anti-reflective coating on the inner crystal face as well as the outer. Interior hazing cannot be polished and means the crystal is due for replacement.
234.30.41.21.03.002
- Confirm the calibre is the 8912 before quoting anything else. This carries a different movement from the Diver 300M despite the identical depth rating, and their published reserves differ.
- Check the lug width against the published 21 mm. That is an odd size that almost no aftermarket strap maker stocks, and a buyer planning a strap change should hear it from you.
- Measure the fit using the published 48 mm lug to lug rather than the 41 mm diameter, which understates how this case sits.
Sources
- OMEGA official product page for reference 210.30.42.20.01.001 (Seamaster Diver 300M Co-Axial Master Chronometer 42 mm; steel) - Case: steel; 42 mm; Dial color: black; Crystal: domed scratch-resistant sapphire crystal with anti-reflective treatment on both sides; Water resistance: 30 bar (300 metres / 1000 feet); Movement: Calibre OMEGA 8800; self-winding movement with Co-Axial escapement; certified Master Chronometer approved by METAS; resistant to magnetic fields reaching 15000 gauss; free sprung-balance with silicon balance spring; automatic winding in both directions; rhodium plated finish with Geneva waves in arabesque; Power reserve: 55 hours; Frequency: 3.5 Hz; listed with a 5-year warranty; Re-read 2026-09-23, the page additionally publishes: Between lugs: 20 mm; Lug-to-lug: 49.90 mm; Thickness: 13.56 mm; Case diameter: 42 mm; Total product weight (approx.): 194 g; Type of Clasp: Foldover clasp with comfort setting and diver extension; Bracelet material: Steel — retrieved 2026-09-23
- OMEGA official product page for reference 234.30.41.21.03.002 (Seamaster 300 Co-Axial Master Chronometer 41 mm, steel) - Between lugs: 21 mm; Lug-to-lug: 48.00 mm; Thickness: 13.85 mm; Case diameter: 41 mm; Case: Steel; Dial color: Blue; Crystal: Domed, scratch-resistant sapphire crystal with anti-reflective treatment inside; Water resistance: 30 bar (300 metres / 1000 feet); Total product weight (approx.): 156 g; Caliber: Omega 8912; Movement type: Self winding; Power reserve: 60 hours; Bracelet material: Steel; Type of Clasp: Foldover clasp with comfort setting — retrieved 2026-09-23
Not affiliated with OMEGA. Specifications are read from each manufacturer's own published documentation on the dates shown and may change; the manufacturer's current documentation governs.