Ethiopian Airlines flies daily from Jimma to Addis Ababa (Birr2622, one hour to 2½ hours depending on route).
Selam Bus has a daily bus from Jimma to Addis Ababa (Birr205, six to seven hours) at 6am.
There are numerous ordinary buses throughout the day for Addis Ababa (Birr125 to Birr145, seven hours). The gates to the bus station compound usually open around 6am. Get your elbows ready and be prepared for a mad scramble.
Amid the early morning free-for-all you’ll find buses for Tepi (Birr 130, eight hours), Mizan Tefari (Birr98, 7½ hours), Metu (Birr110, eight hours), Bedele (Birr66, 4½ hours) and Nekemte (Birr128, nine hours). There are up to six minibuses to Welkite (Birr98, 5½ hours).
Roads (and hence buses and minibuses) also connect Jimma to the towns of southern Ethiopia, among them Awasa and Arba Minch, but you'll usually need to change in Chida or Sodo.