Kings Island is two parks in one, the main amusement park and the Soak City water park. When you buy a ticket, you get admission to both! If you plan to spend a full day, consider splitting the day into parts so that you can cool off and return later to the main park refreshed.
If you want to try a strategy like that, or want to keep your options open, come prepared. You should bring swimwear, flip-flops, beach towels, and sunscreen. If you have small children, they are required to wear flotation devices. There are new puddle jumper style of these that you can buy that are a lot more fun and comfortable for the kids to wear compared to the traditional life vests the park makes available. Don’t worry about dragging all that stuff through the park, you can leave it in the car until you need it.
There may be other local attractions that you want to hit while you’re in the area. If it is hot and crowded and you need an hour or two away from the park, you could also head to one of several nearby malls or IKEA which is fifteen minutes away in West Chester.
Notes from Krystal: Here is another suggestion if you want to head off the property for an hour or two. At SouthWest Golf Ranch, off US 42 going into Lebanon, you can play Putt Putt golf ($7 for adults $5 for children) you can play as many rounds as you want!
If you just need a break, bring a book or tablet and use the amusement parks wi-fi if you just want to be able to sit and relax. If the car isn’t too hot, you can just roll down the windows and take a nap hang out at your car. If you have an SUV or van where seats can fold down, bring a cooler enjoy a snack and a board game. You can also take this time to charge your phone while you plan out the rest of the day.