Thursday 01 Jan New Year's Day
Tuesday 06 Jan Epiphany
Monday 23 Feb Ash Monday
Wednesday 25 Mar National Holiday
Friday 03 Apr Good Friday
Monday 06 Apr Easter Monday
Friday 10 Apr Orthodox Good Friday
Monday 13 Apr Orthodox Easter Monday
Friday 01 May Labour Day Holiday
Monday 01 Jun Whit Monday
Wednesday 28 Oct National Holiday
Thursday 24 Dec Christmas Eve
Friday 25 Dec Christmas Day
Thursday 31 Dec New Year's Eve (Half holiday)
Source: http://www.helex.gr/documents/10180/25792/2015_Trading_Calendar/dfdb2b21-9171-499e-9726-894badcfa974