Deanna Beck from Epic Ocean Adventures said the whales were a common sight on the company's tours between July and November, but Tuesday was special because they had not seen that many on one tour before.
She also said the tour company had a 90% strike rate when it came to spotting pods of bottle-nosed dolphins, and frequently came in contact with sea turtles.
WOW! The most whales we have ever seen on tour today 15! The humpback whales are now starting to make their way south. The next 6 weeks is the best time to see them with #epicoceanadventures #doubleislandpoint #rainbowbeach #noosa #visitsunshinecoast #thisisqueensland #australia #dolphins #whales #holidays #brisbane #kayaktour #springPosted by Epic Ocean Adventures on Monday, September 21, 2015
Humpback whales migrate through the waters off Rainbow Beach on their way to and from Antarctica.
The whales spend the summer in the cooler waters around the pole feeding, but make the journey up the east coast of Australia, and past the South Island of New Zealand to calve in warm tropical waters in winter.
Unlike many migrating whales, humpbacks are most commonly spotted by whale watchers because they prefer to follow the coastline, fairly close to the shore.
The whale migration occurs every year between June and November and has helped to spawn a new branch of eco-tourism, with many charter boat companies now specialising in whale watching tours.
Humpbacks are found in both hemispheres, but those in the Northern Hemisphere spend their winters in the Artic Circle so migrate at different times of the year. Therefore there is no interbreeding between northern and southern humpbacks.
There are 18-20,000 humpback whales migrating to and from Antarctica each year. The species was almost hunted to extinction, with the numbers slumping to about 5000 worldwide before a moratorium was introduced in 1966.
The humpback whale takes its name from the habit of breaking the water surface with a large area of its back when diving.
About 20,000 humpback whales will migrate this season between Antarctica and the Great Barrier Reef.
Humpbacks were the third most endangered species of all the big whales up until 1998, but now their numbers are increasing 13% each year.
They are the fifth largest animal on this planet, growing up to 15m in length with a weight of up to 45,000kg (99,000lbs) - equivalent to 11 elephants or 600 people each.
Humpbacks are the most acrobatic of all of the great whales.
The species displays a wide variety of leaping, rolling and breaching movements which provide fascinating viewing for whale watchers.
The humpback whale is also well known for its complex underwater vocalisations or whale songs particularly during breeding.
Adult whales have been seen to breach 20-30 times within five minutes, displaying awesome grace and power.