There was a Green wave on the green island, seeing the party perform much better than opinion polls predicted.
The Czech Republic is voting over two days, Friday and Saturday.
The UK voted on Thursday but no exit polls available due to national law.
EU elections results will be announced on Sunday evening once all EU nations have voted.
Take a look at our blog below for the latest:
Ireland votes amid renewed Brexit fears
The election of a new prime minister in Britain may lead to a new phase in Brexit negotiations that could be "very dangerous" for Ireland, Prime Minister Leo Varadkar warned on Friday as the country was headed to the polls for EU elections.
"We may see the election of a Eurosceptic prime minister who wants to repudiate the withdrawal agreement and go for no deal or we may even see a new British government that wants to see a closer relationship with the EU and goes for a second referendum," Varadkar told Ireland's Virgin Media News after Theresa May on Friday said she would quit as UK prime minister.
The Irish campaign has been dominated by Brexit fears. Most mainstream parties have campaigned on strengthening the country's role in the European project as the UK, its largest trading partner, is due to leave the bloc.
The border with the British-ruled province of Northern Ireland has been a sticking point in negotiations between London and Brussels.
Ireland will send 11 MEPs to the European Parliament.
Polling stations have opened at 7:00 local time. Voters will have until 22:00 to cast their ballot.
Czech citizens cast their votes as populists top polls
Czech citizens have two days to elect their 21 MEPs. Polling stations opened at 14:00 local time this Friday and will close on Saturday evening
The populist movement of the Czech Prime Minister and billionaire Andrej Babis is favourite despite a wave of anti-government protests and the fraud charges he faces involving European Union funds.
Babis’ ANO (YES) movement tops latest opinion polls with an estimated 25% of the vote, followed by the moderate eurosceptic Civic Democratic Party and the pro-European Pirate party.
Babis wants his country to remain in the bloc but is calling for EU reforms.
The anti-EU Freedom and Direct Democracy part is predicted to win around 10% of the vote and capture its first seats in the EU Parliament.
Britons vote amid Brexit turmoil
A divided Britain was voting this Thursday, nearly three years after the country voted to leave the European Union.
Hundreds of angry EU27 citizens have been turned away from UK polling stations today, campaigners said.
The election, which Britain did not expect to have to take part in, is a result of the deadlock over the way forward on Brexit after Prime Minister Theresa May’s deal with Brussels was rejected three times by lawmakers.
Britons are due to elect 73 Members of the European Parliament (MEPs) but the government said they would not take up their seats if the country leaves the EU by the end of June.
Britain was due to leave the EU almost two months ago, but having delayed its exit date twice and with parliament still deadlocked, it remains unclear how, when or even if it will go ahead with the divorce. It is currently due to leave by October 31.
Opinion polls show strongly pro-Brexit and pro-EU parties are set to gain votes at the expense of May’s governing Conservatives and the opposition Labour Party which have struggled to define their positions on the issue.
According to data from pollsters YouGov, only one in five of those who voted Conservative at the last national election in 2017 are planning to vote for the party on Thursday, with 62% instead planning to back Nigel Farage’s Brexit Party.
In turn, Labour is mainly losing voters to remain-supporting parties.
The Brexit Party, launched last month to take on the political leaders it says have betrayed the vote to leave, is expected to come out on top. A YouGov poll on Wednesday put support for the party, which is campaigning for a ‘no deal’ Brexit, at 37%. May’s Conservatives were in fifth place on just 7%.
With the ‘remain’ vote splintered between several strongly pro-EU parties, including the Liberal Democrats, Change UK and the Green Party, they are expected to win fewer seats.
The result is likely to pile further pressure on May to make way for a new leader as soon as possible. Earlier this month, the Conservatives endured a drubbing in local elections.
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