Icelanders are voting on whether to restart negotiations to join the European Union, in a referendum that opinion polls suggest is too close to call. The result matters because it could reshape Iceland’s economic, trade and security relationships, while reopening a long-running dispute over national sovereignty and control of fishing waters.

Supporters argue that EU membership and eventual adoption of the euro could reduce currency volatility and living-cost pressures, while improving Iceland’s position amid heightened geopolitical tensions in the North Atlantic. Opponents focus on the risk of losing control over fisheries, which account for almost 40% of exports; a Yes vote would begin talks with Brussels but any final membership agreement would require a second Icelandic referendum and approval from all 27 EU states.