Tertius (sandbank)

Island Tidal sandbank in Schleswig-Holstein's Wadden Sea

A sandbank in Schleswig-Holstein’s tidal flats, Tertius appears at low tide and supports shorebirds; visitors join guided mudflat walks, birdwatching trips and occasional seal-spotting excursions.

Tertius is a sandbank located off the coast of Schleswig-Holstein in the German North Sea. It is part of the tidal Wadden Sea and coastal shoal system.

As a sandbank it is a low, dynamically changing landform shaped by tides, currents and storms and does not support permanent habitation or infrastructure. Such features are important for coastal processes and forshorebird and marine habitats.

There is no widely reported history of permanent settlement on the sandbank; its form and position have varied with natural coastal dynamics.

The sandbank lies in the maritime zone off Schleswig-Holstein in northern Germany, within the broader Wadden Sea region of the southeastern North Sea.

How to Get to Tertius (sandbank) #

Tertius has no public harbour or scheduled service. Access is by private boat or charter from North Frisian coastal towns such as Büsum, Husum or Tönning; any landing should be arranged with an experienced local skipper. The sandbank lies in the Wadden Sea (UNESCO World Heritage area), so landing is often restricted; check with Schleswig‑Holstein National Park authorities before planning a visit.

Tips for Visiting Tertius (sandbank) #

Check tide charts and plan any approach with a licensed local skipper-sandbanks shift and are submerged at high tide.
Bring binoculars: the Wadden Sea around Tertius is prime haul-out area for common and grey seals in autumn and winter.
Respect protected-area rules: much of the Wadden Sea is Natura 2000 and part of a national park; landing is often forbidden without permit.