The 662-metre Alssund Bridge crosses the narrow strait between Als island and the Jutland mainland just north of town. The view from the centre of the bridge, looking south down the Alssund towards Sønderborg's harbour, is the postcard view of the town.
There is a pedestrian and cycle lane on both sides. From below, the older King Christian X Bridge in the town centre is a more atmospheric crossing — a 1930s drawbridge that still opens for sailing yachts heading into the Baltic.