Casio watches are cheap enough that counterfeiting them seems pointless — and yet fakes are common, particularly for G-Shock and the popular vintage squares. The margins work because buyers do not inspect a £40 watch the way they would inspect a £4,000 one.
Here are nine checks that catch most counterfeits. None require tools.
1. Check the module number against the reference
Every genuine Casio has a module number — a three or four digit code — printed on the case back alongside the model reference. Each model uses a specific module. If the case back says the watch is a GA-2100 but the module number does not match the one Casio publishes for that reference, it is not genuine.
This is the single most reliable check, because counterfeiters frequently reuse one generic case back across several models.
2. Test the backlight behaviour
Backlight type is model-specific and hard to fake convincingly. An A168 should have an even electroluminescent glow across the whole display. An F-91W should have a weak single-LED light in one corner. A G-Shock should light instantly and evenly.
If a model that should have EL lighting instead has a dim corner LED, walk away.
3. Look closely at the printing
Genuine Casio dial and bezel printing is crisp with consistent stroke weight. Counterfeits commonly show:
- Slightly blurred or feathered edges on small text
- Inconsistent spacing between characters
- Wrong font weight on the "CASIO" or "G-SHOCK" wordmark
- Misaligned printing relative to the case
4. Check the button feel
Genuine Casio pushers have a defined, positive click. Fakes are frequently mushy, inconsistent between buttons, or require noticeably different pressure on different pushers.
5. Weigh it in your hand
Casio publishes weights for its models. A genuine GA-2100 is around 51g; a genuine F-91W is around 21g. Counterfeits often use different resin formulations and come out noticeably lighter or heavier. If it feels hollow, be suspicious.
6. Inspect the strap and keeper
On resin models, look at the moulding around the lug holes and the strap keeper. Genuine straps have clean moulding with no flash — the thin ridge of excess material left by a poorly finished mould. Counterfeit straps frequently show flash along the edges and a keeper that is loose or badly sized.
7. Verify the water resistance marking
Casio marks water resistance precisely and consistently. A G-Shock marked "WATER RESIST" without a depth rating, or marked with a rating that does not match the published spec for that reference, is a red flag. Genuine 200M models say so explicitly.
8. Check the packaging and paperwork
Genuine Casio packaging includes a model-appropriate manual with the correct module number on it. Mismatches between the module number on the manual, the case back and the box are common on counterfeits — the components are sourced separately.
9. Consider the price and the seller
Casio pricing is fairly stable. A G-Shock offered at a fraction of its normal price is not a bargain, it is a signal. Buy from sellers who state clearly that stock is genuine and who will handle a warranty claim.
If you have already bought one
Take clear photographs of the case back, the dial and the packaging, and compare the module number against Casio's published specification for that reference. If they do not match, raise it with the seller or the marketplace immediately — most platforms have a specific counterfeit process with a time limit.
All stock in our Casio collection is genuine, and every reference is listed with its model code so you can verify what you are buying before you order.
Frequently asked questions
► What is the most reliable way to identify a fake Casio?
Check the module number on the case back against Casio's published module for that model reference. Counterfeiters commonly reuse a single generic case back across multiple models, so mismatches are frequent.
► Do fake Casio watches have working backlights?
Usually yes, but often the wrong type. A model that should have an even electroluminescent backlight will frequently have a cheap single-LED light instead.
► Is a very cheap G-Shock always fake?
Not always, but heavy discounting on current references is a strong warning sign. Casio pricing is relatively stable across authorised sellers.
► Does Casio offer an online serial number check?
Casio does not provide a public serial lookup for most consumer models. Verification relies on the module number, physical inspection and buying from a seller who guarantees authenticity.
