To enter the UK, you must hold a valid passport for the duration of your stay. Depending on your nationality, you will either need an Electronic Travel Authorisation (ETA) (e.g., for EU, US, and Australian citizens) or a Standard Visitor visa.

Key Requirements by Nationality • EU, EEA, & Swiss Citizens: You generally require a valid passport. You must obtain a UK ETA prior to travel. Irish citizens are exempt and can continue to travel freely under the Common Travel Area. • USA, Canada, Australia & Most Others: Nationals from non-visa-required countries must apply for and receive an ETA before boarding transport to the UK. • Visa-Required Nationalities: If your country is not on the ETA or visa-exempt list, you must formally apply for a Standard Visitor visa in advance.

The UK ETA (Electronic Travel Authorisation) The ETA is a digital travel permission linked to your passport. • Cost: £16 per application. • Validity: Valid for 2 years or until your passport expires, allowing multiple visits. • How to Apply: Use the official GOV.UK ETA Application page or download the UK ETA mobile app. It is recommended to apply at least 3 days before your trip.

More info: https://www.gov.uk/uk-border-control/before-you-leave-for-the-uk