Paris - London

You probably already know this, but as of today, Eurostar is the only train company connecting France and Belgium to the United Kingdom via the Channel Tunnel.

As for fares, I recommend booking at least a month and a half in advance if you want to find a round-trip ticket for under €100.

Another important point: since the United Kingdom is not part of the Schengen area, passport and security checks can take quite a bit of time. It’s recommended to arrive at least an hour before departure.