Round trip from Denver to Reykjavik for $437

United Airlines has round trip airfares from Denver to Reykjavik for $437, down from $561. The fares include a carry-on bag and allow basic economy options with no seat selection or changes. Travel dates are available from September through December 2026, with several departure and return dates. The deal requires booking directly through United Airlines and planning ahead due to long layovers and seat restrictions. This price offers a significant reduction from the original list price, making it an attractive option for travelers looking for an affordable Iceland trip during the fall and winter months.