Kangaroo Island - How to get there

Personally, I prefer ferry to flight. Because ferry is cheaper and you could also bring your car with you if you like.
By Ferry:
SeaLink operates four departures daily, with additional services during peak times between Cape Jervis and Penneshaw. From Adelaide city to Cape Jervis, you need about 1 and half hour driving. Mainland coach connections are available to/from Adelaide and Goolwa to Cape Jervis. The ticket is $43 one way for an adult and $84 one way for a vehicle up to 5m. You could find whole timetable and book your ticket on www.sealink.com.au. Ferry travelling time is a comfortable 45 minutes. I chose 9am ferry from Cape Jervis to Penneshaw and brought my car with me. You could also rent a car after you arrived Kangaroo Island.
By Air:
Regional Express (REX, Reservations: 13 17 13 or 08 - 8553 2938, www.regionalexpress.com.au) and Air South (Reservations: 1800 339 629 or 08 - 8234 4988 www.airsouth.com.au ) operate the 30-minute flight from Adelaide to Kingscote Airport (KGC). The KGC airport is located 13km from the Island's capital, Kingscote. Shuttle transport to Kingscote is available. Details below:
Airport Shuttle Service
Between Kingscote Airport and all Island townships and accommodation houses. Bookings are necessary. Kangaroo Island Transfers, Ph: 0427 887 575; Smartcar, Ph: 1300 887 121.