I recommend Jamsil Saenae YB Children and Adolescent Hospital.

Introducing YB Children and Adolescent Clinic, located on the 3rd floor of the License Shopping Mall in Jamsil Saenae Station.

There are many pediatric clinics around here, and I've been going there ever since my kids were little.

One of the best things about this pediatric clinic, I think, is that it's open on Sundays from 9 a.m. to 1 p.m. Thanks to this, I can visit the clinic without feeling overwhelmed, even on a Sunday.