Budapest’s public transport is run by BKK and is cheap, frequent and easy to use once you understand the ticketing, which is where visitors come unstuck.
The metro
Four lines, colour-coded and numbered.
M1, the yellow line, opened in 1896 and is the oldest underground railway on the European continent. It runs shallow under Andrássy út from Vörösmarty tér to Mexikói út, with small wooden-panelled stations and short trains. It is a monument you can commute on, and it serves the Opera, the House of Terror, Heroes’ Square and the Széchenyi baths.
M2 (red) runs east-west and crosses the river, linking Batthyány tér in Buda with Deák Ferenc tér, Astoria and Keleti station.
M3 (blue) runs north-south through Pest and serves Nyugati station and the airport bus interchange at Kőbánya-Kispest.
M4 (green) is the newest, opened in 2014, running from Kelenföld through Gellért tér and Fővám tér to Keleti. Its stations are architecturally ambitious and worth a look.
All four cross at Deák Ferenc tér, which is the centre of the system.
Trams
The trams do more work than the metro. Tram 4 and tram 6 run the Grand Boulevard — the Nagykörút — in a long arc through Pest and across two bridges, and between them they are the busiest tram line in the world by some measures. They run through the night. Tram 2 runs along the Pest embankment past the Parliament and is one of the most scenic urban tram rides in Europe; take it once for the ride. Trams 19 and 41 do the same job on the Buda side.
Tickets
A single ticket is valid for one journey on one vehicle; changing metro lines is allowed on a single ticket but changing between a tram and a bus is not. This trips people up constantly.
Buy a travelcard instead. They come in 24-hour, 72-hour and weekly versions, cover everything including the HÉV suburban railway within the city boundary, and remove the whole problem. A 72-hour card pays for itself in about six journeys.
Buy from machines at metro stations, which take cards and have English, or on the BudapestGO app.
Validating
If you have a single ticket, you must validate it before travelling — in the orange or red machines at metro entrances, or on board trams and buses. An unvalidated ticket counts as no ticket.
Inspectors wear armbands and work in pairs, often at metro exits and at the bottom of escalators. Fines are issued on the spot, are substantially higher if you do not pay immediately, and there is no discretion for tourists. This is the single most common bad experience visitors have with the city.
The HÉV
Four suburban rail lines, of which H5 from Batthyány tér to Szentendre is the one visitors use. A city travelcard covers you to the city boundary; beyond it you buy a supplementary ticket, either from a machine or from the conductor.
Taxis and ride-hailing
Taxi fares are regulated and identical across all licensed companies, so there is no point shopping around. Cabs are yellow with a licence number on the door. Do not take an unmarked car, particularly at the airport or outside nightlife areas.
Uber does not operate in Hungary. Bolt does and is widely used. Otherwise call Főtaxi or City Taxi, or use their apps.
Bikes and scooters
MOL Bubi is the city bike-share scheme, with docking stations across the centre and an app. Budapest has decent cycle lanes on the main boulevards and along the river, and Margaret Island is entirely traffic-free. Electric scooters from several operators are widespread and increasingly regulated; pavement riding is not permitted.
Walking
The centre of Pest is flat and gridded and walkable end to end in half an hour. Buda is not — Castle Hill and Gellért Hill both involve real climbs. Plan the hills for the morning and use the trams for the long flat distances, and you will barely need anything else.
Night transport
The metro stops shortly after eleven at night. After that a night bus and tram network takes over, marked with numbers in the 900s and running every fifteen to thirty minutes on the main corridors. Trams 4 and 6 run all night on the Grand Boulevard, which covers a great deal of the ground most visitors need, and night bus 907 and 908 handle the main east-west routes. The night network is well used and normal; it is not a last resort.
Accessibility
The newer lines are good and the older ones are not. M4 was built to modern standards and every station has lift access. M2 and M3 have been progressively fitted with lifts, though not at every station. M1 is largely inaccessible — it is an 1896 tunnel with stairs, and there is very little to be done about it. Newer trams on lines 4 and 6 are low-floor; older rolling stock elsewhere is not. If step-free travel matters, plan around M4 and the low-floor trams, and check individual stations on the BKK site.
One useful habit
Buy the travelcard at the airport machine on arrival, before you need it. It removes every subsequent decision about tickets, validation and inspectors for the length of your stay, and those decisions are the only friction in an otherwise easy system.