Sail with the whales:
July - September
Humpback whales are throughout the Whitsundays in these months, many with newborn calves.
Listen for their songs while snorkelling and be on the watch for their spouts and breaching when sailing.
Don't be surprised if they even come into the anchorage, especially around the northern islands.
You could watch a display right at the back of your boat like this photo - this mother and calf photo was taken in Blue Pearl Bay.