The North Sea formed a barrier to contact between Britain and the Continental regions north of the Rhine prior to the late fourth century AD. Whilst there is evidence for sporadic contacts between these two regions prior to this date, in the main these contacts probably occurred indirectly via the south Dutch/Belgian/north French region. From the late fourth century onwards, we have evidence for considerable cross-North Sea contact, first in the form of Saxon piracy, and from the early/mid-fifth century onwards, as population movements principally directed from north-west Germany to southeast England. The reasons for this change are outlined and discussed.