The film title 303 refers to the Mercedes-Benz O 303 touring bus model, but the motorhome in which the two protagonists travel is actually a Mercedes-Benz Hymer T1 650.
The journey starts in Berlin at Tempelhofer Feld.
Filmed in part, in the Picos de Europa, Spain.
The script for this project was 270 pages long. Hans Weingartner actually shot it completely as he could not imagine on how to cut the story down to feature length. The footage was then cut into a six episode TV show (which was released three years later as 303 - Die Serie (2021)). Only after this, he was able to conceive a way to tell the story in this shorter feature length film.