💵 Cash

Airport security X-ray machines screen for threats, not for cash amounts — TSA and equivalent screeners will not confiscate money simply because you are carrying it. However, if you are entering the US with more than $10,000 USD (or equivalent) and fail to declare it at customs, CBP officers can legally seize the entire amount. The security checkpoint and the customs declaration are two entirely separate processes.

Yes, and the thresholds are set by each country's customs authority rather than aviation security. The US requires declaration of amounts over $10,000 USD, the UK over £10,000, the EU over €10,000, Australia over AUD $10,000, and Canada over CAD $10,000. The rules apply to the combined value of all cash and monetary instruments you are carrying, not just banknotes, so traveler's checks and money orders count toward the total.

Security screeners at the checkpoint are not looking for cash and are not required to report it, but customs and border officers at arrival can ask about large sums and request documentation of their origin. Carrying a legitimate explanation — such as records of a property sale or business transaction — is advisable if you are traveling with amounts near or above the declaration thresholds. Declaring cash proactively is always safer than having it discovered.

Security rules do not require this, but practically speaking, keeping cash in your carry-on is safer because checked bags can be lost or delayed. There is no rule against splitting cash between bags, and it does not affect your obligation to declare the total amount at customs — the threshold applies to everything you are bringing into the country, regardless of which bag it is in.