Rantum (German pronunciation: [ˈʁanˌtʊm] ⓘ; Sölring Frisian: Raantem) is a village and a former municipality on the island of Sylt in the district of Nordfriesland, in Schleswig-Holstein, Germany.

[2]: 86 East of the village are the Rantum-Inge, an ample area of salt marshes and the Wadden Sea.

[2]: 86 The oldest record of the name is found in a nautical chart from 1142, which is today displayed in Copenhagen.

As Rantum was repeatedly destroyed by storm surges between 1362 and 1634 and had to be rebuilt in a different location each time, historical records are only preserved from the 17th century on.

[2]: 105 Beginning in 1936, the Wehrmacht had a 568 hectare area of the wadden sea encircled by a dyke and flooded to create the Rantumbecken (Rantum Basin) as a take-off and landing site for seaplanes.

[2]: 86 In 1977, the small Rantum Harbour was created from the remains of a naval air station pier as a tidally independent marina.

In addition, this has become the venue for the Meerkabarett, the Sea Cabaret, which annually features various artists during the summer season.

A LORAN-C transmitter for radio navigation is located near Rantum, using a 193 metres (633 ft) tall lattice tower mast radiator as an antenna.

Rantum hosts the Weiße Zeltstadt (White Tent City) camp site.