Schools in Barcelona

Help we are a danish family with 3 kids 12, 9 and 5 who are thinking on moving to Barcelona. My kids do not speak Spanish and only the girl on 12 speak a little english. We were thinking on the international schools but they are expendsive. We have not tryed to moved aboard before, so we need some advise.
Please help us with some advice on schools in Barcelona

Don't forget the official language of Catalunya is Catalan. If they are in the public system, they will have to learn Catalan. I can't tell you if 'Spanish' (i.e. Castillian) is compulsory or optional.

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