The cheapest flight to Barcelona you can get by boooking just before departure.
The most popular airlines on the route Dortmund - Barcelona: Germanwings (4U).
The cheapest flights you can book on the route Dortmund Airport (DTM) - El Prat (BCN).
There is no direct flight on the route from Dortmund to Barcelona
Il volo con scalo più breve dura 3h 50min.