Fitzroy island is closest to the mainland and it takes no more than 45min to reach it by ferry from Cairns. The word ferry is used loosely in this case. There is one trip in the morning(8:30h) to the island and one trip back in the afternoon(17:00h). There is a great chance of seeing whales(for free!?!) on the way and the price is lower than any of the other companies around.
The only way to get to Fitzroy Island is by ferry. It is a 45 minute trip from Cairns to Fitzroy Island. There are 3 departures a day from either side:
Dep. Cairns: 8.30am, 9.30am, 10.30am & 3.45pm
Dep. Fitzroy: 9.30am, 3.00pm, 4.00pm & 5.00pm
(Check the website for any changes)
It's a nice ride, and you can sit up top in the sun (although make sure to put a hat and sunscreen on) or below (the seats are more comfortable inside the ferry as the ones on the top are plastic)
Well, there's really only one way to the island and that's by ship. The ferry service runs from the Trinity Wharf in Cairns to Fitzroy and runs several times a day. Reservations in advance are encouraged, but the ship is pretty big so I don't think it will be too much trouble to get a spot on the boat. The ride takes a mere 45 minutes and it's over before you know it. You pull in onto the pier where you disembark the ship and prepare for all the fun. Before disembarking, the crew makes you well aware of the last ship for the day, so be on time for that one unless you plan to overnight on the island.
There is one option to get to get to Fitzroy Island, and that is to take the Fitzroy Island ferry. It's a nice 45 minute trip towards this island just off the shore. A round ticket cost around 36 dollars (2004) and there only a few departures daily, so it's best to book in advance and make sure that if you stay over on the island that you have your accommodation arranged.
Ex Cairns: 8.30am, 9.30am, 10.30am & 3.45pm
Ex Fitzroy: 9.30am, 3.00pm, 4.00pm & 5.00pm
Here is a good boat service between cairns and Fitzroy Island. The journey lasts abpout 40 minutes and offers beautyful views over the australian coast and the ocean.