Hi- We are transferring in Heathrow in a few days. We arrive in Terminal 5 and need to get to Terminal 3. We have about 2.5 hours and it's all on British Air so our bags will go through to our destination in the US. Is there any preference on how to get between terminals- the London Underground, a train, or a bus. Any suggestions as to what is easiest? Thank you!
Use this link to learn how to get from one terminal to the another: https://www.heathrow.com/at-the-airport/airport-maps/travel-between-terminals.
If you are on one ticket you can use Flight Connections. Just follow the signs and you will take a bus between terminals. You will stay airside and not go through immigration, although you will have to go through security. So be careful that you are not carrying liquids bought after security on your first flight.
2.5 hours should be plenty of time for the transfer as long as your first flight is not too late.
Go to this website, put in your flight information, and you will get step by step instructions.
http://www.heathrow.com/flight-connections
Since your bag is being transferred to your next flight, you will be able to use "Flight Connections." Just make sure when you check in for your first flight, you get the boarding pass for the second one.
Do not follow the crowd to immigration (border control.) You don't need to do that. Follow the purple Flight Connections signs and they will get you Terminal 3.