Greek Easter (March/April): Most important religious holiday. Dates vary by Orthodox calendar. Midnight Saturday resurrection service, firecracker celebrations, lamb roasts on Sunday. Atmospheric but book accommodation far ahead.
Athens Epidaurus Festival (June-August): Ancient Greek dramas, opera, dance, and concerts at Odeon of Herodes Atticus and Epidaurus Theatre. World-class performances in historical venues.
Independence Day (March 25): Military parade on national holiday celebrating 1821 revolution. Combined with Annunciation religious feast.
Ohi Day (October 28): National holiday commemorating Greece's refusal of Italian ultimatum in WWII. Military parades and celebrations.
Athens Marathon (Early November): Follows original marathon route from Marathon to Athens. International event with thousands of runners.
Apokries (Carnival - February/March): Three-week carnival before Lent with costumes, parades, and festivities. Greek version of Mardi Gras.
Feast of Assumption (August 15): Major religious holiday. Many Athenians vacation, some businesses closed. Religious processions throughout Greece.
Athens International Film Festival (September): Independent and international cinema screening throughout the city.
Thessaloniki Festival Season: While in Thessaloniki, it influences Athens cultural calendar with film, documentary, and art events.
Cultural events concentrated June-September. Check official Athens tourism website for current festival schedules and tickets.