W n W do post on their facebook page when they have reached capacity and are closed for more arrivals. They also suggest a time to come later that day.

With all the publicity the park is getting over the concert and being over capacity, more people might realise they should check before they leave home - that they will be able to get in to the park.

We live about 1.5-2 hours away. I imagine there could  be quite a few people in surrounding areas of Sydney, that would head for the water park in the holidays and may find they can't get in. Although we do have a big water park nearby, which was the largest Water theme park in NSW before W n W opened.

No you can't book in. It would be what ever number is allowed that get there first, that get in.