Until a few years ago there was a regular car ferry service from the UK to Hamburg, which was then curtailed to Cuxhaven, and then dropped altogether. So today the only sea crossings are to neighbour destinations, from where onward travel has to be by rail or road.
The DFDS Seaways service (www.dfds.co.uk) runs from Harwich to Esbjerg, in Denmark, three times a week, and could be useful for anyone contemplating a trip to northern Germany, the Baltic coast and the former east. DFDS Seaways also run a daily route from Newcastle to Amsterdam (two hours from Germany) which cuts out a lot of driving time for anyone from the north of England or Scotland. Both are relaxed, overnight journeys with good on board facilities, and more like mini cruises than ferry crossings.
The Stena Line service (www.stenaline.co.uk) runs between Harwich and the Hook of Holland (two hours from Germany) with day-time and night-time crossings, and a journey time of six and a half hours. This service is well plugged in to the rail networks of both the UK and the Netherlands. Not so long ago there was also a choice here of a fastferry catamaran on the route, but susceptibility to bad weather and competition from low-cost airlines made it uneconomic.