How much cash to actually bring

Enough to be fine for two days without a working card. Rarely more.

The default answer for most destinations: bring a small amount of local currency or hard currency for the first day, and get the rest from an ATM after you arrive. Carrying a trip's worth of notes means carrying a trip's worth of risk, and you will have converted it all at a rate you chose under time pressure.

What to arrive with

• Enough for the first 24 hours. Transport from the airport, a meal, a tip, a SIM. Usually a modest amount.
• An emergency reserve in a widely-accepted currency. US dollars or euros in small, clean, undamaged notes. Kept separately from your wallet.
• Two cards, stored in different places. More useful than more cash.

When to bring considerably more

• Remote or small-island destinations where the nearest working ATM may be a ferry away.
• Countries with unreliable card networks or frequent ATM outages.
• Places where foreign cards frequently fail, which is a real phenomenon in a handful of countries and worth checking recent traveller reports for.
• Visa-on-arrival fees, which are often cash-only and sometimes in a specific currency.
• Trekking, diving or festival trips where you will be away from infrastructure for days.

Declaration limits

Most countries require you to declare cash over a threshold — commonly the equivalent of around 10,000 US dollars or euros — when entering or leaving. It is a declaration rather than a restriction, but failing to declare can mean confiscation. Check both the country you are leaving and the one you are entering.

Separately, some currencies cannot legally leave their home country at all. See closed currencies.