Mandø is reached from the Wadden Sea Centre in Vester Vedsted, about 12 kilometres southwest of Ribe. The Mandøbussen tractor bus departs from the Centre and crosses the tidal flats in around 40 minutes; the schedule is governed entirely by the tides, so check the current timetable on the Mandøbussen website before you go. Bookings are recommended.
By car, you can drive across the Låningsvejen causeway during the hours when it is passable — again, consult the tide tables carefully. A standard car handles the crossing in dry conditions; the track is unpaved but maintained. If you miscalculate the tides, you will need to wait several hours for the next low water window.
Ribe, the nearest town and the oldest city in Denmark, is an excellent base. It is well served by buses from Esbjerg, which is the nearest rail junction.