The Channel Islands use pound sterling (GBP), but each island — Jersey, Guernsey, and Alderney — issues its own banknotes and coins. These are interchangeable on the island of issue but are not accepted on the other islands or in the UK. If you're island-hopping, spend your island-specific cash before you leave, or exchange it. UK notes are accepted everywhere.
The islands are not part of the European Union, which means no VAT on most goods and no EU consumer protection rules. Alcohol and tobacco are notably cheaper than in the UK. Shopping in St Helier or St Peter Port can save money on perfume, alcohol, and electronics, though the EU no-longer allows duty-free imports from the Channel Islands in the way it once did for online purchases.
Emergency services: dial 999 as in the UK. Healthcare is not free at the point of use for visitors — there are reciprocal arrangements with the UK, but you should carry a UK Global Health Insurance Card (GHIC) and check what it covers. Travel insurance is advisable.
Tipping is similar to UK norms: 10–15% at restaurants if service isn't included. Most places accept card payments. English is the working language on all islands; French is used in some official contexts, particularly in Jersey, and older residents may speak Jèrriais (Jersey Norman French) or Guernésiais.
Mobile roaming: UK mobile networks generally include the Channel Islands in their plans without extra charges, but check with your provider — some treat the islands as international destinations.