Athens has an extensive and reliable bus service that covers not just the city but all the suburbs and surrounding areas. All of the buses are modern, eco-friendly and thankfully air conditioned. To give you the full bus routes and timetable is too extensive for this website as most tourist to Athens will probably never need to use the buses as the metro service in the city is so good.
KTEL is the national bus service which connects all of Greece, the main station in Athens is in Peristeri on the main highway. From here you can travel to practically anywhere in Greece, from Corfu in the north-west to Tripoli in the south. If you don't mind travelling by bus this is a great way to get around the country as it is inexpensive.
The Athens Tram service is very modern only being completed just before the Olympics in 2004. There are 4 lines of the tram system - Aristophanis, Aischylos, Thukydidis and probably most important to tourists is Aristotelis which connects Syntagma in the centre to Glyfada at the beach.
Unlike some cities around the world, taxis in Athens can't be missed, all are painted bright yellow and are so numerous it seems as if every other car is a taxi.
There are many Taxi ranks in Athens but most are usually hailed from the roadside which is normal in Athens. The Taxis are very cheap due to all the competion, this why sometimes drivers will pick up two separate fares at the same time, this is illegal but does happen. As with most cities the Taxis in Athens charge fares by using metres and a minimum charge.