The trip is 4 days and it is going to be in spring and during the school holidays.
Hi Becky, there are lots of family activities on the Gold Coast! It is basically THE place to go for attractions in Australia! Apart from visiting the beautiful beaches - the most famous section is Broadbeach which is a long stretch of beautiful golden sand lined with all the hotel skyscrapers, shops and restaurants - there are also lots of theme parks such as Sea World Gold Coast, Dreamworld, Warner Bros. Movie World, Wet'n'Wild Water World and WhiteWater World. Other attractions are the Currumbin Wildlife Sanctuary and Currumbin Valley rock pools, the Glow Worm Caves, Mount Tamborine where you can do a lovely little skywalk through the rainforest and botanical gardens as well as visit Thunderbird Park, the skywalk climb to the roof of the highest building (very safe!) plus lots of smaller experiences such as horse-riding etc which have a vast selection of places. At Broadbeach and Surfers Paradise there are some cool attractions I used to take my kids I cared for to a lot such as Ripley's believe it or not museum, 7D cinema, Infinity Attraction and lots more (hard to remember but just walk around and you will see)! Not to mention lots of beautiful parks scattered all over the coast with some great themes and play equipment for the kids. Honestly, the Gold Coast is like kid paradise!
Things to watch out for - if it is in the holidays you are going to get huge queues at the theme parks especially. If you want to go I recommend buying a multipart ticket to get the best value - there are a few different ones available to pick up in advance or once you arrive. Personally, if I had just 4 days I would spend a day at Broadbeach playing at the beach and then some of the attractions around there that I mentioned - they are only roughly 30-60 mins each but not cheap! Another day I would do Currumbin Wildlife Sanctuary. Day 3 Movieworld and possibly one other park if time. Day 4 either more parks or possibly a trip to Mount Tamborine and the attractions there.
Hope this isn't TOO much information! :)
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I made a video about fun things to do on the Gold Coast. You can watch it here:
The theme parks are awesome. Best value is to purchase annual passes and you have unlimited access to the parks while you are here.