Omega · Authentication
Seamaster 300M: real vs fake
The Seamaster 300M is Omega’s dive icon, recognizable by its wave dial and the helium escape valve at 10 o’clock. Replicas give themselves away with crude wave execution, a crooked valve and a weak Seahorse engraving on the caseback. Photograph the dial, valve and caseback and verify with LegitCheck AI.
What to check on the Seamaster 300M
Model-specific zones — on top of the brand-level signs.
Helium escape valve at 10 o’clock
The Seamaster 300M has a helium escape valve at 10 o’clock — a separate screw-down crown. It is cleanly integrated into the case, with even threading and a crisp action. A missing, tilted or dummy valve is a clear replica tell.
Wave dial
The signature laser-engraved wave pattern is even, with consistent spacing and depth across the whole dial. On fakes the waves are uneven, "smeared," or look printed on top rather than engraved.
Seahorse caseback engraving
The caseback carries Omega’s Seahorse (Hippocampus). The engraving is deep, with crisp lines and an even medallion outline. A small, flat or blurred seahorse is typical of copies.
Dial printing & markers
The "Seamaster", "Professional" and "300m / 1000ft" text is printed sharply, the applied markers and logo are straight, and the lume is filled densely in a single tone. Painted or misaligned text is a red flag.
Bezel and its action
The unidirectional diver bezel turns counterclockwise only with crisp clicks, no play and no backplay, and the insert markings are even. A bidirectional or mushy bezel gives a replica away.
Where to inspect
The key zones to photograph and check on this type of item — a schematic, not a product photo.
- 1Dial and printing
- 2Bezel and markings
- 3Crown
- 4Bracelet and links
- 5Serial and engraving
The difference is in the details — drag the slider
Typical differences in workmanship: stitching consistency, edge finishing, detail quality. Left — factory quality, right — common replica flaws.
Replica 
Authentic Photo angles for the check
- 1 Dial
- 2 Caseback
- 3 Crown
- 4 Bracelet
- 5 Serial number
Check your Seamaster 300M right now
Snap photos of your item and get an AI verdict with a confidence score in about a minute.
FAQ
Where is the helium escape valve on a Seamaster 300M?
On the side of the case at 10 o’clock as a separate screw-down crown. A missing or dummy valve on a model that should have one is a serious reason to doubt authenticity.
What does a genuine wave dial look like?
The waves are laser-engraved in even rows with consistent spacing and depth across the dial. An uneven, smeared or "printed" pattern is a typical fake tell.
What should be engraved on the caseback?
Omega’s Seahorse (Hippocampus). The engraving should be deep and crisp; a flat or blurred seahorse is a replica marker.
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