Entry & Visas
Greece is a member of the EU, which is why EU citizens do not require a visa. In addition, there are generally no border controls within the EU. You only need to carry your identity card with you.
Time
Eastern European Time (UTC+2) applies.
Credit cards & ATMs
There are ATMs everywhere in the cities. Outside of cities, however, you should always have enough cash with you. You can always pay by card in restaurants and other establishments, but if you are unsure, it is better to ask.
Best time to visit
It depends on what you want to do and where you want to go. If you want to go to the beach, May to September is the best time. In winter, however, you should only go to the best-known islands (Mykonos, Crete, Santorini), as the smaller islands are only geared towards summer tourism. You can go on a city trip all year round.
Driving
A national driving license is sufficient for EU citizens. The road network is well developed and the roads are generally in good condition. The traffic signs and rules are largely standardized within Europe.
The speed limits are 110 km/h on freeways, 90 km/h on motorways, 70 km/h outside built-up areas and 50 km/h within built-up areas. The blood alcohol limit is 0.5 per mille in the blood and 0.25 per mille in the breath
You can find more information here.
Phone
If you have a phone contract from the EU or the Schengen area, you do not pay any roaming charges. You can therefore use your phone at the same rate as at home.