Paris–London · practical comparison
A flight result shows time in the air while a train result shows time between stations. For a fair decision, compare the same route from your real starting point to your real destination.
Flying also includes getting to the airport, the pre-departure buffer and onward travel after landing. Eurostar also involves passport and baggage checks before boarding. The useful question is therefore: how much total time, how many transfers and how many constraints are involved from my actual start to my actual destination?
Start and finish at the same places“Gare du Nord to St Pancras versus Charles de Gaulle to Heathrow” mixes unlike journeys. A fairer comparison is:Train: your Paris address → Gare du Nord → checks and waiting → Eurostar → St Pancras → your London address.Plane: your Paris address → Charles de Gaulle → airport buffer and checks → flight → Heathrow → your London address.
Eurostar also requires time before departureFor London services, Eurostar explicitly requires passport and baggage checks before boarding. For London St Pancras, the operator currently recommends that Standard and Plus passengers arrive around 75 minutes before departure and Premier passengers around 45 minutes before departure. Treat this as planning guidance, not as a universal last-possible-arrival time.Do not calculate the rail option using only the scheduled time between Gare du Nord and St Pancras. Add a realistic buffer based on the current guidance for your ticket, and check it again shortly before travelling.
For a flight, add the time before and after the flightParis → Charles de GaulleRER B is one of the main rail options for CDG. Île-de-France Mobilités gives a rough journey time of about 25–30 minutes and a frequency of roughly every 6–15 minutes. That does not mean “Paris to the plane takes 30 minutes”: add the trip to the right station, waiting time, the walk to the terminal and airport procedures.How early should you reach the airport?For short-haul flights, Heathrow currently recommends arriving at least around two hours before departure. This is planning guidance rather than a universal deadline for every airline and airport. Keep the recommended airport arrival time, the airline's check-in or bag-drop deadline, and the gate/boarding deadline separate.Heathrow → LondonHeathrow Express states a 15-minute journey between Heathrow Central and Paddington, with roughly another six minutes for Terminal 5; trains normally run every 15 minutes. But Paddington is not all of central London, so add the onward journey to your real destination.
Compare five rows, not two numbersFive parts of the journey to compare door to doorPart of the journeyEurostarPlaneAccess before departureaddress → Gare du Nordaddress → CDGTime before departurerecommended buffer + checksairport buffer + check-in/security/boardingMain transportEurostarflightAccess after arrivalSt Pancras → addressHeathrow → addressTicket conditionsprice, changes, baggageprice, changes, baggage
When the train may be more practicalEurostar deserves serious consideration when your starting and finishing points are convenient for Gare du Nord and St Pancras. Much of the airport access then disappears. Fewer separate connections can also be useful, but that does not guarantee rail will always be faster.Compare baggage and ticket-change conditions too; they may matter more than a small timetable difference.
When flying may be the sensible choiceIf your Paris start is convenient for CDG, your London destination is convenient for Heathrow or Paddington, or a particular flight fits your schedule much better, the overall result can change. If Heathrow is a connection to another destination, “central London” may not be the right endpoint for the comparison at all.
What about price? Check comparable tickets at the same timeChoose a specific date and roughly comparable travel window.Check direct train and flight options in the same session.Add the baggage you will actually carry.Compare change conditions if flexibility matters.Include the cost of reaching and leaving the airport or station.There is no permanent “price winner” that can be represented by one fare: without comparable tickets for the same date, that number becomes stale quickly.
A quick decisionStart by checking Eurostar if both ends of your journey are central and you want fewer separate transfers.Take flying seriously if access to CDG and onward travel from Heathrow are convenient or a particular flight solves an important scheduling problem.Do not decide yet if you have compared only the scheduled flight time with the train time or only two advertised starting fares.
Sources to check before travellingEurostar — check-in: current station-arrival guidance and checks for London services.Île-de-France Mobilités: current Paris-airport access and RER B guidance.Heathrow — travel tips: current airport-arrival guidance.Heathrow Express — journey time: current Paddington–Heathrow journey time and frequency.Checked 8 September 2026. For a real trip, use current operator guidance and the conditions attached to your ticket.
