Fitzroy Island is a rocky island about 45 minutes by ferry from Cairns. It has some nice snorkelling offshore and a few walking tracks which offer you great vistas over the ocean.
You can use the facilities of the run-down resort near the ferry pier.
In the late 19th century the island was used as quarantine station for Chinese immigrants and you still find some graves from that period.
Nowadays Fitzroy Island is a Nationalpark.
There are a three departures per day from Cairns and the return trip costs 42 AU$.
Fitzroy island is covered in Tropical Rainforest and is accessed by catmaran from Cairns Harbour. It is surrounded by coral reefs and is good for snorkelling. There is a walk up to a lighthouse which has good views. There is also a small sandy beach here called 'Nudey Beach', which features in alot of the Cairns posters.