London Heathrow Airport

Heathrow’s two recurring puzzles are the same ones every time: which terminal you need, and which train to take into London. Get both right before you travel and the rest is straightforward.

Which terminal

Heathrow has four working passenger terminals: 2, 3, 4, and 5. Broadly, Terminal 5 is British Airways and its partners, Terminal 2 is the Star Alliance carriers, Terminal 3 is a mix that includes several oneworld and Virgin Atlantic flights, and Terminal 4 covers many SkyTeam and other international airlines. Airlines do move between terminals from time to time, so check your boarding pass rather than trusting memory — and note that 2 and 3 are within walking distance of each other, while 4 and 5 are separate stops requiring the train or a transfer bus.

Getting into London

Three rail options share the underground station, and they suit different priorities:

• Heathrow Express is the fastest — a nonstop run to Paddington in about 15 minutes. It is also the most expensive, and Paddington may or may not be where you actually want to be.
• The Elizabeth line is the value pick: slower (roughly 30-45 minutes to central London) but far cheaper, and it runs straight through the middle of the city to places like Bond Street, Farringdon, and Liverpool Street. For most travelers this is the sweet spot.
• The Piccadilly line Underground is the cheapest and slowest — close to an hour to the West End, with every stop along the way. Fine if you are not in a hurry and your hotel is on the line.

By road, Heathrow is about 23 km west of central London, and traffic on the M4/A4 can turn a taxi into a long, costly trip. Trains almost always win.

Connecting

Airside transfers between Terminals 2 and 3 are walkable. Moving to or from 4 or 5 means an internal transit ride and, often, a security recheck, so give a connection through those a generous cushion — Heathrow’s minimum connection times are optimistic on a busy morning.