In my notion only "im Urlaub" is usually in use. One other two variants might be legit. But I do not know any person expressing "in Urlaub" and I would say "auf Urlaub" is just slang. Comply with along with the video below to discover how to put in our https://bihlmayermedia-bilder.com/urlaub/wir-sind-im-urlaub/