1916
DST timeline
Daylight saving time in Ireland has 3 recorded changes on record, spanning 1916–2019. The earliest documented event is the adoption in 1916: Ireland adopted summer time while still part of the United Kingdom's wartime clock-change system. The most recent is the reform vote in 2019: Ireland remains affected by the unresolved EU clock-change reform debate. As of the latest data, Ireland is shown as "Debating" in our daylight saving tracker, which is the practical takeaway for anyone scheduling calls, travel, or deliveries against this region today.
Ireland legally defined standard time as GMT+1, making winter time the offset period from 1971 onward.
Each entry records a distinct daylight saving milestone for Ireland. An adoption marks the year clocks first began shifting; an abolition marks the year the country stopped changing them and settled on a single year-round offset; a modification covers changes to the start or end dates, the size of the shift, or which regions take part; and a reform vote records a legislative or parliamentary decision that may not yet be in force. Years reflect when the change took effect, not when it was announced, so a 2019 vote and a later effective date can both appear.
Daylight saving rules change more often than most people expect, and historical offsets are exactly the detail that breaks date math for past timestamps, travel records, and historical scheduling. If you only need today’s behaviour for Ireland, the current-status link above is the fastest answer; if you are reconstructing a past date or comparing several countries, the full timeline and the linked sources below give you the authoritative record.