The vote is expected to be a close-fought race, with opinion polls showing a near dead heat between those who want Iceland to hold talks on joining the bloc and opponents who say the North Atlantic country should remain independent.
IS THIS A VOTE ON EU MEMBERSHIP?
No. The referendum is only a vote on whether to negotiate with the EU. If Icelanders say "yes", this would trigger two or more years of bargaining with Brussels followed by a second referendum, possibly in 2028, on whether to join the bloc.
WHAT HAPPENS IF ICELAND SAYS NO?
The government frames its membership plan as a "now or never" moment. Prime Minister Kristrun Frostadottir told voters in August that a "no" would put all EU speculation aside.
WHAT WOULD ICELAND GET IF IT JOINS THE EU?
Supporters say membership would help Iceland boost its economy, stand up to larger trade partners and withstand Arctic rivalry under U.S. President Donald Trump, who has said he wants control over the neighbouring island of Greenland.
It would become part of the EU customs union, a trading area without internal tariffs and with common external tariffs on goods that enter from the outside.
The country could adopt the euro currency, replacing the volatile Icelandic crown, in a bid to address inflation and generally high living costs, and bring down interest rates.
Iceland would become a member of EU decision-making bodies, including the union's executive arm, known as the European Commission, as well as the elected European Parliament and the European Council, where heads of state and government meet.
WHAT ARE THE ARGUMENTS AGAINST JOINING THE EU?
Membership would hand power and influence to Brussels, and would not in itself strengthen Iceland's security, the opposition says.
The fisheries industry, a pillar of Iceland's economy and a symbol of national identity, fears that joint resource management under the EU's Common Fisheries Policy will open the door to foreign vessels in Icelandic waters.
By keeping its own currency, the krona, Iceland would retain a cushion against changing economic fortunes, allowing it to weaken against the euro and the dollar during downturns and to rise when the country's economy performs well.
WHY NOW? AND WHO IS FOR AND AGAINST?
Reykjavik walked away from EU accession talks in 2013, four years after applying, when a Eurosceptic government took power. Since then, rising living costs and the war in Ukraine have revived public appetite for reopening the question.
The centre-left government coalition formed in 2024 agreed to put EU membership talks to a vote at the initiative of Vidreisn, the most pro-EU party.
Frostadottir's own Social Democrats are pro-EU but have stayed quieter and the coalition's third party, the People's Party, opposes membership outright.
The opposition Independence Party of Gudrun Hafsteinsdottir leads the "no" side.
WHAT IS IN IT FOR THE EU?
Bringing Iceland into the bloc would extend the EU's reach in the Arctic at a time when the region has become a growing focus of great power competition.
The island nation, a NATO member with no army of its own, is located in a stretch of ocean known as the Greenland-Iceland-United Kingdom gap, or GIUK, one of the North Atlantic's most strategically vital chokepoints for Russian naval movements.
Iceland would also be easier to integrate than other nations currently discussing membership, requiring less reform than Ukraine or countries in the Western Balkans, making it a rare case where accession could move relatively quickly.
