Originally Posted by
csycsycsy
But if we're talking customs ..Can't think of a border that divides two EU country-regions but one of which is not in the EU customs Union...maybe one of those islands or enclaves that are not in thr regular customs/vat union?
Yep, that would be the only ones: Livigno for Italy, Heligoland and Büsingen for Germany and Ceuta and Melilla for Spain. You also have the special cases of some overseas territories but these are normally either both within EU territory and customs union or out for both.