There is a certain logic to it. A relative is flying home on Friday, you have cash in a drawer, and the fee on a transfer is a visible, annoying number. A cash envelope has no visible fee. The temptation is understandable, and the arithmetic, once you do it, is not kind to it.
The fee you do not see
Sending cash by hand or by post replaces a fee with a risk. The fee is certain and small. The risk is uncertain and large, and the whole sum is exposed to it. Economists have a name for choosing a small certain cost over a tiny chance of a big one: insurance. Cash in the post is the reverse, an uninsured gamble paid for with the saving.
It is also a gamble with unusually thin protection, as the next sections show.
What postal services say
Start with the rules of the carriers themselves, which vary a good deal. Even within one country the answer can depend on which service you buy, how it is registered and what the destination permits, so the label on the counter is not enough.
Australia Post says plainly that it will not deliver bullion, bank notes or coins in any international service. That covers Australian and foreign notes and coins alike, even if the destination country would accept them.
Royal Mail does not ban cash outright on its compensation page, but says there are restrictions on sending cash to some destinations, and its compensation for cash, securities or bearer instruments on International Tracked services is capped at £100. It also requires a certificate of posting for any claim, and claims must be made within six months of posting. (These terms were read in November 2026 and Royal Mail updates them, so check the current scheme.)
The US Postal Service’s International Mail Manual, in an archived January 2020 edition, treated currency as restricted in international mail and warned that the destination country may prohibit it. The present wording is unconfirmed here, so check the current manual before relying on any of that.
Pattern, then. Some posts refuse the item, some limit what they will pay if it vanishes, and nearly all of them tell you to read the destination country’s own list of restrictions.
A worked example: the cost of a lost envelope
Say, for illustration, you post £500 in notes to a relative, using a tracked international service. You save the transfer fee. Say a transfer through a regulated provider costs between 1.5 and 3 per cent of the amount in total (illustrative; real totals vary by corridor and provider), which on £500 is £7.50 to £15.
If the envelope is lost, the maximum compensation under the Royal Mail cap quoted above would be £100, and only with a certificate of posting and a claim within six months. The net loss is £500 minus £100, which is £400, plus the postage.
So the posting only wins if the chance of loss, theft or seizure stays below about £15 divided by £400, or roughly 3.8 per cent at the top end of the transfer cost, and below about 1.9 per cent at the bottom. For a one-off, that sounds small. For a regular monthly habit, it compounds quickly: the envelope has to arrive every single time.
A tracked bank transfer, by contrast, leaves a record, has a named recipient and goes through a regulated provider with a complaints route. You can see the rate before you commit; our GBP to INR page is one place to check what the market rate looks like. Rates refreshed hourly. Cash has no such benchmark, and no receipt that shows what the recipient was actually given at the other end, which matters when family members disagree about how much was sent.
Customs: the threshold that catches families
Border rules treat cash as something to be declared above a modest threshold, and the thresholds are lower than people assume.
- Great Britain: GOV.UK says to declare cash of £10,000 or more, or equivalent, when carrying it between Great Britain and a country outside the UK. Family or group totals count even if each person carries less. Failing to declare can lead to seizure of all the cash, and a penalty of up to £5,000 to get it back.
- European Union: travellers entering or leaving the EU with €10,000 or more in cash, or the equivalent, must declare it. The limit applies to each person individually, so splitting cash among a group does not change who has to declare what they carry. The European Commission says “cash” includes banknotes, coins and bearer instruments such as cheques and money orders. For cash sent unaccompanied by post, freight or courier, customs may ask for a disclosure form, and may act on smaller sums if they suspect crime.
- United States: a report, FinCEN Form 105, is required for more than $10,000 in currency or monetary instruments moved across the border. A federal regulator’s page says the requirement covers currency sent by mail or shipment as well, and that someone who receives more than that amount from abroad without a report having been filed must report it too.
Now the family arithmetic. A made-up family of three, each carrying £4,000 for a relative’s house purchase, is carrying £12,000 between them. That exceeds £10,000 and, under the GOV.UK wording, the group total counts. Each person is under the threshold. The family is not.
Splitting a sum into smaller pieces to stay below a threshold is also a poor idea in itself. US law (31 U.S.C. 5324) separately prohibits structuring, or helping to structure, a cross-border movement of currency to evade the report, with penalties that include up to five years in prison. Whether that charge applies in any given case is for a lawyer to say.
The traveller problem
Whoever carries your cash becomes the person answering for it. If customs asks, they are the one explaining where the money came from and who it belongs to. Your relative may not know the declaration rules. They may not know the amount of cash a given country’s border treats as unusual. They may be asked questions in a language they find stressful.
And the money is exposed on the way. A bag can be lost or stolen, and no one holds a record of the cash. Whether any travel insurance covers cash, and up to what limit, is a question for the policy itself.
There is a quieter hazard. You may not know what else the traveller has agreed to carry. “Someone asked me to take this” is a thin explanation to give at a border, and the traveller is the one giving it.
What cash is actually good for
None of this means cash has no role. Small amounts handed over in person, within one country, on the day of use, are fine. So is a gift pressed into a visiting relative’s hand when they are standing in front of you and spending it in the same place. Money a traveller takes for their own trip is their own business, within the declaration limits. The trouble is the specific combination of crossing a border, going unrecorded and being unrecoverable.
If the reason for the envelope is that the recipient lacks a bank account, there are regulated answers: cash pickup, mobile wallets and bank-account-free options are covered in our guide on sending to someone without a bank account. If it is cost, comparing total cost usually shows the gap is smaller than the fee line suggests. And if it is a sense that official channels are too much trouble, scams to avoid explains how the formal route protects you.
Sources
- Australia Post: What is a valuable item?
- Royal Mail: International compensation
- USPS International Mail Manual (archived January 2020 edition)
- GOV.UK: Take cash in and out of the UK
- European Commission: EU cash controls
- CFTC: International transportation of currency or monetary instruments reporting
- US Code: 31 U.S.C. 5324, structuring transactions to evade reporting
Checked: November 2026
