The metro has four lines and the M4 links the airport to the centre in about twenty minutes. A single ticket costs 0.80 euros, one with transfers within 30 minutes also 0.80, one for 60 minutes 1.10; a day card costs 2 euros, a 24-hour card including night services 3 euros and a 72-hour card 7.60. They are bought at station desks and machines, or loaded onto electronic cards. The same tickets work on trams, trolleybuses and buses, including those that climb Vitosha. From the airport (Sofia Vasil Levski, SOF, about 7 km from Alexander Nevsky Cathedral as the crow flies): the simplest way is the M4 metro, from the station at the east end of Terminal 2, about 20 minutes to the centre at €0.80 a ride, payable by contactless card straight at the gates. For the central station, change to the M2 at Serdika. Watch out: if you arrive at Terminal 1, first take the shuttle bus to Terminal 2.
- From the airport take the M4 metro: 0.80 euros and twenty minutes to the centre, which removes the unlicensed taxi problem in one move.
- The 3-euro 24-hour card also covers night services and pays for itself in four rides: doing Boyana and Vitosha the same day makes it worthwhile at once.
- For Vitosha you want bus 66 (Aleko), 61 (Golden Bridges) or 64 (Boyana): the Simeonovo and Dragalevtsi lifts are not running, so height has to be earned on foot.
- The Roman Serdica complex is crossed free by passing through the metro station: it is a pedestrian shortcut rather than a visit to schedule.