Ferries from the UK to Germany
No scheduled ferry links a British port with a German one. The last passenger service ran from Harwich to Hamburg, moved downriver to Cuxhaven in March 2002 and was withdrawn in November 2005. DFDS still sails Cuxhaven to Immingham, but that is a freight route and the terminal's approval does not extend to fare paying passengers. Denmark is no way round the gap either: Harwich to Esbjerg, the last passenger ferry between Britain and Scandinavia, made its final crossing on 29 September 2014.
What is left are three land bridges. Choosing between them is really a decision about how much driving you are prepared to do at the far end.
Via the Netherlands: the shortest onward drive
Harwich to Hook of Holland is the quickest at sea. Stena Line runs four sailings a day, from 6 hours 30 minutes, so a morning departure still gives you a useful afternoon on the road.
Hull to Rotterdam is the overnight alternative, about 11 hours 30 minutes on a 20:30 departure. P&O puts Europoort two and a half hours from the German border and central Germany a little over six hours from the berth, which is the shortest drive available from any UK crossing.
Newcastle to Amsterdam leaves at 17:00 and takes roughly 16 hours 45 minutes to IJmuiden. From northern England and Scotland it saves more road miles than it costs sea hours, and DFDS itself points travellers bound for Hamburg down this route. The full set of Dutch crossings is on the UK to the Netherlands page.
The overnight sailings buy a cabin and a night you would otherwise spend in a hotel. That, more than the timetable, decides most bookings.
Via the Channel: fastest crossing, longest road
Dover to Calais takes about 90 minutes; Dover to Dunkirk takes two hours, with up to 22 DFDS sailings a day. Both leave the longest drive of any option, right across northern France and Belgium before Aachen. They earn their place when your route already runs through Kent, or when you want a departure every hour instead of one a day.
LeShuttle through the Channel Tunnel is the fastest way to move a vehicle: 35 minutes platform to platform, with passengers staying in the car. Motorhomes, caravans and trailers travel on single deck carriages. Fixed LPG tanks up to 47 kg are allowed if less than 80 per cent full, but vehicles that run on LPG are refused.
Without a car
Only the Dutch route works properly on foot. Stena Line's Dutchflyer sells a through ticket from any Greater Anglia station, London Liverpool Street included, to Hook of Holland, where the metro connects to Schiedam Centrum and the Dutch rail network. P&O carries foot passengers at Dover; DFDS does not on its French routes, and LeShuttle takes nobody who is not in a vehicle.
When rail or air is the better answer
With no vehicle to move, the ferry is a detour. London to Cologne by train via Brussels takes just over five hours, against a full day for any sea route. For Berlin or Munich, fly.