From Athens International El. Venizelos airport:

Take Attica Highway in the direction towards Elefsina for 20 km. At the "Kifissias" exit merge into Kifissias avenue and head towards the suburb of Kifissia for 3 km. Turn right at the Zirinio Gymnasium and take Kiriazi street up to Kolokotroni street. At the end of Kolokotroni street you will find Filadelfeos street and Theoxenia Palace Hotel right on Kefalari Park.