"The departure will be tomorrow."
Translation:Η αναχώρηση θα γίνει αύριο.
"Η αναχώρηση είναι αύριο" has also the same meaning and is totally correct. The present tense in Greek can be used to express events that will certainly happen in the future (or even in the past). http://users.sch.gr/ipap/Ellinikos%20Politismos/Yliko/Theoria%20Nea/xronoi-rim-NE.htm