We decided to visit a Lego Park with my son, who's very fond of all kind of lego buildings!
I cannot decide which one to chose among those in Europe..
My budget is small and moreover I would prefer one not too far from the airport and with comfortable transfers
My son cares about most possibilities to experience activities in the park..
I would recommend the original Legoland Parken in BillundDenmark. Billund has an international airport that is serviced by Ryanair direct from Italy (and by other airlines with connections) and Legoland is a few minutes away from the airport by car or public bus. Lego's headquarters and factory are also in Billund (although, they don't do regular tours of the factory).
I have been to the Legoland in Denmark and California, and most of the rides are the same, but I preferred Legoland Parken. It is older, but has a real charm to it and the rides are pretty much all the same. The main difference with the newer parks versus the original Denmark Legoland is that there are more rides for older kids at the California (as its newer) and I've heard the same is true for the newer Legolands in Germany and the UK. That being said, for kids under 8 or so, the Denmark Legoland has everything you need and is very charming.
But the biggest recommendation I would make is to try to stay in the LEGOLAND Billund Resort if you can afford it within your budget. The hotel has its own entrance into the park and is filled with lego models and bins of legos for the kids to play with. I think the Legoland Hotel combined with Legoland park is a really great family experience and if you can make it work within your budget, you should do it. The Legoland hotel in Billund is older and it isn't overly nice, but the overall experience is pretty fantastic.
So, if your son is under 8 or under, I would definitely recommend Denmark and if he is older, I would still recommend Denmark, but the other options would be great too. It should be noted that Denmark is very expensive in general, so if it doesn't work within you budget, do the the Legoland in Windsor, England and try to stay at the Legoland Windsor Resort Hotel.
Hope that helps.
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I very much agree with the previous poster and would just like to add that if you fly from Italy then you can also connect to Billund Airport with Lufthansa, Air France, British airways and KLM who all serve the airport aswell as Ryanair.