Dubrovnik domestic and international buses leave from the Main bus station located in Gruž Port.  Tickets are bought at the Main Bus Station in Dubrovnik.

The following schedules show departure and arrival times for buses leaving Dubrovnik for 2012.

http://www.absolute-dubrovnik.com/dubrovnik-transport-information/item/domestic-and-international-bus-connections-from-dubrovnik?category_id=18