Although Cairns is generally thought of as a place where 20-somethings come to get drunk, check out the Reef and basically have the time of their lives, there is actually a fair amount to do if you're traveling with kids, so don't let the backpackers scare you off.
There's plenty of physical activity with swimming in the waterfalls, lakes and lagoons nearby; rollerblading on the Esplanade; mountain biking in Smithfield Mountain Bike Park; bushwalking in any of the National parks, State Forests or other wilderness areas; or horseback riding at a variety of clubs for riders of any level.
Small children will enjoys Muddy's play area on the Esplanade and the "Lagoon" man made beach, which is safe and sandy and has toilet/changing/snack facilities very nearby.
If your kids crave an adrenaline rush, you could let them do a tandem jump with Paul's Parachuting ( 1800 005 006) or a tandem bungee jump at the AJ Hackett Bungey Tower - of course, if bungee jumping is too scary for the little ones (and really, who wouldn't be scared of such a thing?!), then they can try the Jungle Swing (07) 40577188.
There are also a ton of different entertainment options in Cairns and the areas surrounding it - Sugarworld Waterslides theme park, Cairns Esplanade Swimming Lagoon and Goldpin Lanes (tenpin bowling) are just some of the fun and exciting things to do.
When it's time for a little less physical activity and a little more brain stimulation, bring the kids over to the Tjapukai Cultural Center in Smithfield just 20 minutes north of Cairns. Here parents and kids will learn all about the Rainforest People, the Kuku Yulangi and their customs through dance performances and an interactive village. Call for more details: (07) 4038 1555 . Make sure to benefit from the special children's activities, including a didge lesson, and boomerang painting (they get to take the boomerang home at no extra cost, which is a nice little plus)
Visit one of the seven Natural Wonders Australia’s Great Barrier Reef it has something for the whole family, spend a few days surrounded by the crystal clear blue waters, be amazed by the abundance of marine life onboard Reef Encounter www.reefencounter.com.au or a day trip on Reef Experience http://www.reefexperience.com.au or for more Great Barrier Reef information call 61 7 4051 5777.
If your little ones want to see animals, check out the zoo, or, if you are short on time, the Wildlife Dome on top of the Casino where they can cuddle a koala (for a price) and get up close with Goliath the salt water crocodile. Tickets at the Wildlife Dome are valid for a week so you can come and go a few times if you like.