Highway buses connect Kobe Airport and Sumoto four times daily (two hours, �2000).
A highspeed ferry used to run between Sumoto and Kansai International Airport but this service
By car
The inter-island expressway will get you from Akashi to Naruto, but it isn't advised unless you're willing to part with �5000 in tolls. Furthermore, signage is in Japanese and may be incomprehensible to a foreigner.
By bus
A more affordable option than private cars are highway buses, which charge around �600 for crossing the bridge and �1800 for a one-way trip from Kobe to Sumoto.
By train
There are no direct train services to Awaji Island. Highway buses run directly from major train stations, such as Shin-Kobe on the shinkansen (�1800 to Sumoto), and Osaka and Sannomiya stations on the regular JR line (�2300 and �1800 to Sumoto, respectively). From Shin-Osaka station you must either take a local train one stop to Osaka station, or remain on the shinkansen to Shin-Kobe, to transfer to the bus.
Buses to Awaji Island are not valid with the Japan Rail Pass. Tickets can be purchased from "Midori-no-Madoguchi" locations at each station.
By ferry
Even cheaper and more scenic, but available for the northern crossing only, are ferries that cross from Akashi to Iwaya for a mere �320 on the slow boat (all of 24 minutes) or �450 for the fast boat (a zippy 13 minutes) via the Jenova Line located south of JR Akashi Station