Before you pack: Greece uses Types C and F, 230 V and 50 Hz. At 230 V the supply matches what UK and European appliances expect, so no converter is needed.
The same socket system is used in Türkiye, Latvia, Romania and Kosovo, so one adapter covers all of them. Watch out when moving on: Malta, Cyprus and the United Kingdom use a completely different system. 31 of the 50 destinations in Europe share the plug types of Greece.
Protective earth
Grounded and ungrounded sockets may occur
Greece has sockets with a protective earth (Type F) and without (Type C). A plug that fits mechanically does not guarantee earthing.