How many islands are in the "Whitsunday Island" group that is situated off tropical Queensland, Australia?

There are seventy-four (74) islands that make up this group of islands.

Actually known officially as the Cumberland Islands, this island group was discovered by Captain James Cook, an English explorer on Whitsunday (also called Pentecost - a day of celebration in the Christian calendar) in 1770, and he named the passage between them as Whitsunday Passage.

Common usage has contracted the name from the 'Cumberland Islands of the Whitsunday Passage' to simply the 'Whitsunday Islands', and this is how they are known to the world, and importantly it is how they are marketed to the world.

Only a few are inhabited and those are primarily tourist resorts to allow people from all over the world to come, stay amongst and enjoy the pleasures of the 'Whitsundays' such as snorkelling, boating, para-sailing, and all manner of water sports!!

The islands that are visited the most are Hamilton Island, Lindeman Island, Hayman Island, Long Island and Hook Island as they have operating tourist resorts built on them. There were resorts also on South Molle Island and Daydream Island, but they fell into disrepair after sustaining major damage during a recent tropical cyclone (2017), and as such are presently not open in that capacity.