"I am going abroad."
Translation:Jadę za granicę.
Ah ok, I see now why you would suggest "idę za granicę". Even though it sounds like an equivalent of "Ich gehe über die Grenze", it is in fact something like "Ich laufe ins Ausland".
For crossing a border you might say "jadę/idę przez granicę" or "przekraczam granicę" (often used figuratively).
I understand that "Jade za granicę" is a kind of fixed expression for going abroad, and indeed it equals the German "Ich fahre ins Ausland". And I can see that you're really an expert in German language as you said "Ich laufe ins Ausland" and not "Ich gehe ins Ausland", which is a fixed expression for "I'm moving to another country".
I do appreciate this conversation, but I think I can't go on here because the space is getting too narrow on my mobile :D