Thursday 01 Jan New Year's Day
Thursday 02 Apr Maundy Thursday
Friday 03 Apr Good Friday
Sunday 05 Apr Easter Sunday
Monday 06 Apr Easter Monday
Thursday 23 Apr First Day of Summer
Friday 01 May Labour Day
Thursday 14 May Ascension Day
Sunday 24 May Whit Sunday
Monday 25 May Whit Monday
Wednesday 17 Jun Icelandic Republic Day
Monday 03 Aug Bank Holiday
Thursday 24 Dec Christmas Eve (from noon)
Friday 25 Dec Christmas Day
Saturday 26 Dec Second Day of Christmas
Thursday 31 Dec New Year's Eve (from noon)
Source: https://www.timeanddate.com/holidays/iceland/2015#!hol=9