The metro does most of the work
Beijing's metro has more than two dozen lines, English signage throughout, and fares that start at three yuan. It is air-conditioned, frequent, and almost always faster than a car in traffic. Every station has security screening at the entrance — bag through the scanner, water bottle out for a sip test — so allow a few extra minutes.
The lines you will use most: Line 1 for Tiananmen East and the Forbidden City; Line 2 for the Drum Tower, Lama Temple and the railway stations; Line 8 for Shichahai and the hutong lanes; Line 4 for the Summer Palace area and Beijing South station.
From the airports
Capital Airport (PEK) is 25 km north-east of the centre. The Airport Express runs to Dongzhimen in about 25 minutes for 25 yuan, which connects you to Line 2 and Line 13. A taxi to the city centre takes 40–60 minutes depending on traffic and costs around 100–130 yuan including the expressway toll.
Daxing Airport (PKX) is 46 km south. The Daxing Airport Express reaches Caoqiao in about 20 minutes and links to Line 10 and Line 19; the fare is around 35 yuan. Taxis are expensive and slow at peak times — the train is almost always the better call.
Taxis and ride-hailing
Taxis are metered and reliable, and drivers rarely speak English, so have your destination in Chinese. DiDi, the local ride-hailing app, has an English interface, shows the fare upfront, and removes the language problem — it is what most visitors end up using.
Avoid the roads between 07:30 and 09:30 and again between 17:00 and 19:30. In those windows a 6 km trip can take 45 minutes, and the metro will beat it comfortably.
Getting to the Great Wall
Badaling has its own high-speed railway from Beijing North station, taking around 30 minutes; it is the fastest public option and also the busiest section of wall. Mutianyu is 70 km north-east and has no rail link — a private car takes about 90 minutes each way, and shared tourist buses leave from a few fixed points in the morning. Jinshanling and Gubeikou are further still, and only make sense with a car and a full day.
Practical notes
Bike sharing is everywhere and excellent inside the second ring, where the lanes are flat and the traffic is slow. Helmets are not provided.
Tiananmen Square requires a reservation made in advance through the official mini-program, and it is checked at the security cordon — this catches people out, because the square is on the way to the Forbidden City and you cannot simply walk through.