The best way to beat the summer heat in Korea would be to visit the Caribbean Bay – the biggest water park in Korea. Caribbean Bay is a part of the Everland Amusement Park at Yongin and is easily accessible via city buses from Gangnam, Yangjae, Sadang, Suwon and various other places.

If you love to be in water then Caribbean Bay is the place to be. The entire park has this Caribbean and Pirates theme and they have many an exciting water slides, wave pools, surfing, spa, sauna, indoor and outdoor pools and jacuzzi to keep you busy throughout the day. Plus they have many a snack and food outlet which serves yummy food.

Beach chairs, lockers, towels, life vests are available on rental. You need to purchase bay coins which can be traded for food and rental once you are inside the park. A few things to remember:

1. The Caribbean bay is most crowded as this is this Gold Season also the ticket prices are high.
2. Since the place is crowded the waiting time for slides would be around 60 minutes minimum.
3. The bay coins are available for a minimum denomination of 30,000 won. The balance would be refundable at the counter once you are done for the day.
4. The best ride to relax was the lazy river. Where you sleep on a float and let the river take its course to navigate your float across.
5. Surf ride was best too but the wait time was too long. But that would be the case with any ride.
6. A few places where you would be not expected to wait for long would be the sauna, spa , jacuzzi, pools, wave pools, river but it will be crowded anyways.
7. The food and beer is easily available at various counters and is yummy.
8. If you buy tickets on your credit card you get awesome discounts on your ticket.
9. It takes around an hour to reach Caribbean bay by bus from Gangnam so it is better to leave early in the morning to avoid the long queues.
10. For more details you can visit their website here and here.