On this day, they were harrassing us to bring them to the swimming pool but we were low on energy and a water playground seems to be a good trade. Y is more comfortable with playing with water while K does not like water getting into his eyes very much. It's easy to see who had a better time from the pictures below.
The Splash Park is located at Sembawang Shopping Centre and it's opened from 11am-2pm and 5pm-8pm. There is also a sheltered dry playground and it's a great bad weather back up.