Amami Airport has direct flights to/from Tokyo, Osaka, Fukuoka and Kagoshima with Japan Airlines (JAL) or JAC.
Ryukyu Air Commuter (RAC) operates a daily flight between Naha and Amami-Ōshima. There are also flights between Amami-Ōshima and the other islands in the Amami group.
Travelling by sea, Marix and A Line run their own ferries along the same routes for the same rates, but on alternating days, from the Nazeshinko Ferry Terminal. If you find that one does not offer a route on the day you wish to travel, simply book with the other company.
Marix and A Line run four or five ferries a month from Osaka/Kobe (¥15,120, 29 hours), as well as daily ferries to and from Kagoshima (¥9050, 11 hours) and Naha (¥9570, 13 hours).