UK visitors from dozens of countries will have to pay a new entry fee starting this week

If you're traveling to the U.K. as early as this week, you might need to apply online for a travel authorization before you go.

Starting Wednesday, the U.K. will require U.S. citizens, Canadian citizens and nationals from more than three dozen other countries to have a so-called electronic travel authorization, or ETA.

Here's what travelers need to know:

The ETA is a pre-authorization for travelers from countries where the U.K. doesn't require visas.

The U.K. launched the program in 2024 for visiting citizens from Bahrain, Kuwait, Oman, Qatar, Saudi Arabia and the United Arab Emirates. On Wednesday, it takes effect for a host of additional countries.

Travelers will still need to clear immigration upon arrival. The U.S. has similar digital authorization requirements for nationals from European Union countries, the U.K., and other countries whose citizens aren't required to have a visa to enter. Later in 2025, EU countries will require them of U.S. citizens and nationals from other countries with similar criteria.

You do not need an ETA if you have a visa and are authorized to live, work or study in the U.K.

You can apply online using the U.K.'s ETA app for Android and iPhone. It costs £10 (about $12.50) to apply, and it's good for two years and for visits of up to six months. The fee is paid by credit card.

Travelers will have to upload photos of their passport and of themselves to apply.

Applicants could wait about three days for a decision, sent via email.

Each person eligible for the ETA will need one, including babies and children.

You'll need an ETA even if you're traveling to a U.K. airport for a connecting flight to another country.