Two senses of both "depart" and "departure" are 1) going from one place to another, and 2) leaving one job and taking another job.
For sense 1, it seems that "depart/departure" should be followed by preposition "for", not "to":
He departed for London.
After his departure for London, .....
For sense 2, it seems to make sense that "depart/departure" should also be followed by "for" and not "to". But then, I saw this:
link
Nemanja Vidic's departure to Inter Milan has already been confirmed
So, should "depart/departure" be used with "for" or "to"?