<map lat='51.02' lng='2.28' zoom='11' view='0' float=right width=500 height=200 country=France/> Dunkerque (English: Dunkirk, Dutch: Duinkerke, German: Dünkirchen) is a major port town at the Channel with ferries across the English channel to Dover (norfolklines – crossings every 2 hours). The ferries are free for hitchhikers, if you find someone to give you a lift onto the ferry.
There is a roundabout right next to Polyclinic Villette on Avenue du Stade. Cars can park there quite easily, also on the parking spot right next to it. McDo is close to this position, too, for asking people. Furthermore there is a traffic light a little bit ahead towards the river, which also marks the end of possible spots to stand with a sign or the thumb since there is no place to stop a car and the traffic is getting too fast. See the English channel page for more information about options for crossing the channel.
East towards Belgium
It also must be possible in the above mentioned spot to get lifts towards Belgium. The first petrol station in Belgium is Mannekensvere just after exit 3, Nieupoort, and a further one is at Jabbeke, shortly before Brugge.
It is less busy and more laid-back/friendly than the Calais-Dover route. Both the Calais-Dover boats and the Dunkerque-Dover boats do not charge for extra passengers in vehicles. While Calais-Dover ferries allow foot passengers (cost about £15/20Euros), it is not possible from Dunkerque, so you have no other choice than to get a lift.
Since mid October busses around Dunkerque are free, so from Dunkerque city centre, it is possible to take a free bus in the direction of Loon-Plage. Close to the ferry is a hotel parking lot at the roundabout, which is a good place to be dropped off. The best way to catch a ride from there is walking a little bit in the direction of the ferry. Be warned the signs 'car ferry' on the roundabout point in the 'wrong' direction here, not many cars take this exit because it is a detour towards the ferry. It is faster to take the first exit (when coming from Dunkerque direction). To catch all cars & vans who will cross the Channel walk 10 min to the next roundabout.
Crossing takes about 1h50 and on the Norfolkline ships there provide free wireless internet access.
How to get to the port
Ferries leave from Port Ouest.
To get there from Dunkerque, take a bus A (i.e. from the city center/railway station), going towards Loon Plage (various terminus possible). Get off at Maison Blanche (about 12km, 30min), walk up to the big roundabout. From there you have 3km left - I recommend walking, but if you have time, you can always try to hitch.
If on the A16 motorway (Calais <-> Dunkerque) take the Exit 24.
Before the port there is big parking place for trucks and lorries (about 1km square). It is very easy to get a ride over there. Many vehicles on Polish, Romanian, Turkish and Slovak numbers. But you can find some English, Irish or German ones as well.
A bit further, there is a car park, just in front of a ticket office. You can probably try to get a lift asking drivers there. Usually you have to explain that they pay for car and not for amount of people, but correct number of passengers must be on their ticket. Changing booking is free of charge and takes less than a minute. Always have your documents ready to show to drivers, so they know you are not an illegal immigrant.
Once on the ferry
Once you are on the ferry, it is an excellent idea to ask around for a lift. It is far easier to do this, than to hitchhike when you land. The best tactic is to approach individuals directly and say something like "Excuse me, sorry to bother you. I am trying to hitchhike to [destination]. I don't suppose you could give me a lift in that direction?" Most people on the boat will speak English. Do not try to get a lift by standing at the stairs from the car deck with a sign. It does not work well.
Important for Non-EU Nationals (including US citizens)
There are UK passport controls in Dunkerque and if you do not have the proper papers, you may encounter a lot of hassle, including being denied entry. Worse, the friendly driver who gave you a ride might also face delays.
Upon arrival in Dover, UK customs also have a tendency to check far more cars than any other EU country, the UK is not part of the Schengen Agreement, so you might consider leaving the ferry as a foot-passenger to save your driver a potentially substantial delay! (Not possible if you arrived using Norfolklines)
If you look respectable, are from a respectable country, USA, Australia, New Zealand, to name a few, you are unlikely to have any problems entering the UK, even as a hitchhiker. Show a passport from Somalia, Pakistan or Iran, to name a few that are somewhat less respectable in the eyes of the UK government, expect lots of hassle, including being denied entry.
If you think you will fall in the latter category, you should consider going on to Calais, Norfolkline, which sails from Dunkerque does not take foot-passengers, and spend the money to buy a foot-passenger (return) ticket yourself to avoid causing trouble for your driver, although that does not in any way reduce the risk that you're denied entry either at UK immigration in France or upon arrival in Dover.
As with any border crossing, it helps if you look respectable, even if you come from the EU or respectable countries, and have money (or better, a credit card) to support yourself.
Calais is an alternative to cross the Channel. Sailings from there are far more frequent and all shipping companies take foot-passengers, although at least some (P&O) no longer do so on every sailing or in the middle of the night!