The quake rocked areas of Leinster, including parts of Carlow, Kildare, Wicklow and Dublin, at about 4.15am on Wednesday morning.
Scores of people reported "intense shaking" and a rumbling noise lasting up to five seconds
The epicentre of the earthquake in the Irish Sea was 15km away from the town of Abersoch, Gwynedd, in Wales, and measured a magnitude of 3.8, the British Geological Survey (BGS) said.
It happened at around 4.15am and was felt as far away as Southport in Merseyside.
More than 100 reports from people who felt the earthquake have been made to the BGS, who said the majority were within a 100km radius.
"This was a larger than average earthquake, we get around one a year of this size," it said.
"People have reported hearing an initial loud banging, followed by rumbling, and intense shaking."
The tremor was too small to cause any damage, but residents took to Twitter to share their experience.
Shuana Casey wrote: “Omg actually can't believe I experienced an earthquake in Ireland...freaked me out”
Just Frank gave a humourous take, writing: “Tremors reported in Dublin after earthquake over Irish Sea. They're trying to freak us out before the game. #England #Ireland #Wembley”
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