Athens has a complex and effective network of transport, thanks to the Olympic Games of 2004. Metro, buses, tram and trolley buses, can take anyone in any place of the Attica region.
The distances are usually short but elongated by the delays, traffic and stupid car drivers. Nevertheless It is a trustworthy alternative for those that either can’t or don’t want to use a rental car or a taxi. Another plus, is that you can visit many places of interest that are located in nearby stations and stops. Like this one for example:
http://www.nova-era.gr/the-runner/
In order to travel around the city with any means of transportation, you will need an electronic ticket. It is rechargable and offers a variety of prices and routes. You can ask in a metro station or in kiosks to fill it with the ammount of money you wish. I strongly reccomend the «more than one ticket» per time, because it is more convenient and also reduces the cost. More information: https://www.athenstransport.com/english/tickets/
Some things you should be careful about.
- Do not trust people who tell you that they are conductors, if they do not have a small card with their photo on, hanged on their neck.
- In some kiosks and stations, there is no option to buy ticket with credit or debit card.
- Some ticket ATMs are used only to fill the tickets and not to issue new ones.
- Not all tickets are valid to travel to and from the airport. Check the screen or ask someone.
- Sometimes the transport in Athens stops due to short-announced strikes. Before you start your day, check online if everything works.
- Not all means of transopration operate 24 hours. Some of them have a gap between 00.00 and 04.30 am give or take.
- Guard your belongings. The pickpockets are thriving.
- If you are a bicyclist, search for the term of carrying your vehicles in all means of transportation. Same goes for you who travel with pets.
My advice is to use the transport as much as possible because it will grand you with the opportunity to get deeper in the core of the city, experiencing some things that an organised tour can’t give you. And enjoy.