Begin your Paris to London day trip in the center of the French capital, where you'll meet your host and get your round-trip Eurostar ticket. Board the 8:13am train, which deposits you in London at about 9:30am after a 2 hour 15 minute trip.
Arrive at London's St Pancras station to meet your London host and receive your ticket for the hop-on hop-off bus tour of the city. Your host escorts you to the St Pancras station bus stop and leaves you to see the English capital independently. To get right to your hop-on hop-off tour, take the Station Connector black line to whichever sightseeing bus stop you wish (you can change to the red line at Baker Street if needed). Climb aboard the next double-decker bus to start your introduction to the city. Click on 'View additional info' below to see a map of the bus routes.
The sightseeing bus tour offers an ideal overview of London's centuries of history, with an informative audio commentary available in multiple languages to explain the sights around you. Hop off the bus at any point that you want to explore on foot, including sights such as Big Ben, the Tower of London, Westminster Abbey, Buckingham Palace, Piccadilly Circus, Trafalgar Square and the Houses of Parliament.
Your hop-on hop-off sightseeing ticket includes a cruise on the River Thames, too. To take advantage of this, disembark from the bus tour at the Westminster stop and board the nearby boat to see the city from a different vantage point.
The day is yours to construct as you like, and in London your options are plentiful. Visit a world-famous museum. Stroll through a picturesque park. Enjoy lunch and a pint in a traditional English pub.
After roughly eight hours in London, make your way back to St Pancras station (be sure to leave enough time after sightseeing to return to the station on time) to climb back on the London-to-Paris Eurostar for the return trip to the French capital. You'll arrive at Gare du Nord station in the evening.