Record advance voting exceeding 21 percent of the electorate by August 28 signals unusually strong engagement in Iceland’s August 29 referendum on resuming EU accession talks, a tightly contested national issue framed by the government as a “now or never” decision. Recent parliamentary and presidential elections posted turnouts near 80 percent, while past referendums ranged more widely, creating a baseline traders weigh against referendum-specific mobilization patterns. The narrow polling margin, focus on fisheries, sovereignty, and economic stability, and extended early-voting window have sustained participation without clear precedent for exact levels. Weather on election day, last-minute undecided voters, and comparisons to lower-mobilization referendums remain variables that could separate the leading 70–85 percent bands from lower or higher outcomes in real time.