The Kunisaki Peninsula is the home of Oita Airport, which has domestic flights to Tokyo, Osaka and Nagoya throughout the day on ANA, JAL, Jetstar and Solaseed Air. There are also twice weekly flights to Seoul, South Korea, operated by the budget airline, T`Way Air.
You can reach the airport from Kitsuki, Hiji, Beppu and Oita city using the Airport Limosine Bus, which runs multiple times an hour directly to and from Oita Airport. Oita Airport also has bus services running to other various points within Oita Prefecture, however they are not all that frequent.
The best way to get around the Kunisaki Peninsula is by car as there are limited bus services and no railway connections, the nearest train station being in Kitsuki. Multiple car rental agencies are available at Oita Airport.
The Suonada Ferry runs multiple times a day between Taketazu (the northernmost reaches of Kunisaki Peninsula, bordering Taketa City) and Tokuyama in Yamaguchi Prefecture, only an hour and a half drive from Hiroshima City.