We didn't book when we went in July, so I think you should be OK in June. Danish school holidays start about the 2nd week in June, and go on til mid August.
we didn't book either - had a great time altho the weather was mixed and it certainly ain't cheap, try and be there for the Midsummer's Day Celebration
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But itīs all right now, I learned my lesson well.
You see, ya canīt please everyone, so ya got to please yourself
Ricky Nelson
CampingCheques will also give a good reduction but there are not too many Danish sites on the CampingCheque web site - and you would have to email the camp site to see if they accept cheques in the peak periods. For camp sites in Denmark you need a special pass, can be bought on arrival at all camp sites.
Used to camp regulary in Denmark as i was living in Germany at the time. Not to far into Denmark approx 40 mins or so from the German border is a nice town called "Sonderborg" there are plenty of campsites in the area some even have their own beachs . The sites are very cheap, would definatly "wing it" (dont book) just turn up they are never full. Would stock up on beer & wine, food etc en-route as alcohol is expensive in Denmark
Don't forget to leave a review of the French and other European campsites you have visited!