There is quite a bit for a four year old. At IOA, there are two kiddie playgrounds. There is also Seuss Landing which has 4 different rides that are suitable and the playground. At Jurassic Park there is a bigger playground and the ride Pteranadon Flyers. There is a Discovery Center as well with lot of fun interactive dinosaur things. The four year old will also enjoy the Sinbad show. Over in Toon Lagoon, there is a big boat called Me Ship, the Olive which is lots of fun for kids. The four year old can go on the Popeye water ride and also Storm Force Accelatron which is a teacup type of ride. At the Wizarding World, they can do the little coaster Flight of the Hippogriff and also do the Castle tour.
At Universal Studios, a four year old can do Shrek, Disaster, perhaps Men in Black depending on height. They can do the Animal Actors Show and ET and the Woody Woodpecker coaster. There is an entire kiddie area over by the coaster that also has a Barney show.
This summer, Despicable Me will open and they can do that as well.
I'm sure I have missed some stuff.
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