Going around Sofia using a taxi is fast and convenient, but the public transport is also well developed and allows you to reach any location within the city considerably fast. Here you can find the following information:
Map of the public transport lines (buses, trolleys, trams)
Schedules and routes (buses, trolleys, trams)
Real-time schedules using a GPS (buses, trolleys, trams)
Although the links above are from the English versions of the sites, some things are not translated, to you can use Google Translate.
A ticket costs 1 lev. You can also buy a pass with 10 tickets for 8 leva. Luggage with dimensions larger than 60x40x40 centimeters is charged with a separate ticket!
If you don’t have a ticket when you enter the vehicle, buy one from the driver and perforate it immediately. Inspectors may appear at any time, especially if you get on around the Central Bus Station or Sofia Airport!