The Hawaii that people normally visit consists of 6 islands: Oahu, Maui, Kauai, the Big Island, Molokai, and Lanai. Traveling between these islands usually consists of air or boat travel. Here are your options:
Ferry service: Currently available only between Maui and Molokai or Maui and Lanai. The Hawaii Superferry says they are coming in 2007 and will operate between the Oahu, Maui, Kauai, and the Big Island. (man, I can’t wait!)
Cruises: There are several cruises that will get you to Hawaii, and one that goes strictly from island to island, but you normally can’t stray from the cruise itinerary or get on for just one leg or selected legs of the journey. I’ve asked. It’s best to only consider a cruise if you are more interested in the cruising aspect than Hawaii and you don’t mind only one day or so in each port.
Airlines The three major airlines in Hawaii that provide inter-island travel flights are Aloha Airlines, Hawaiian Airlines, and Go! Airlines
Traditionally, Aloha and Hawaiian Airlines have been charging a minimum of $79 for one way travel between any two islands, but with the entrance of Go! Airlines into the market in mid 2006, prices of $30 to $50 one way have consistently been available.
