If your preferred mode of travel is via bus, you're in luck- you can essentially get to and from anywhere in Spain and Europe through Spain's extensive bus system. Granada's bus station is located a bit out of the way in the city outskirts- in fact, you'll probably have to catch a city bus or a cab to get to it. However, once you get there you can set off for anywhere from the Sierra Nevada to Belgium! 
Granada Bus Station
(Estación de Autobuses de Granada)
Carretera de Jaén, s/n
Tlf: 958 18 54 80
Granada Bus Station Companies:
-Alsina Graells Sur (Tlf: 958 18 50 10)
-Autedia Maestra (Tlf: 958 15 36 36)
-Autobuses Granada-Madrid (Tlf: 958 25 13 50)
-Autocares Bonal (Tlf: 958 27 31 00)
-Bacoma (Tlf: 958 28 42 51)
-Linebus/Autogranadina (Tlf: 958 63 52 74)
-Julia Vía Internacional (Tlf: 958 23 23 00)
