Where do expats in Bangkok typically send their elementary school aged kids?

Believe it or not expat elementary age kids pick up Thai quite easily. My kid goes to Prem International in Chiang Mai and it is crazy to walk around and see how many farang kids speak perfect Thai.

At Prem, Thai is mandatory part of the daily curriculum same as English.

My 8 year old (American) son can speak, read and write perfect thai.

Any well know International School will be fine

Besides ISB, RIS is another excellent school.

Beware of schools claiming to be International just to make money

If the parents are Brit, Bangkok Pattana. If American, ISB (International School at Bangkok). Google it.

There are huge loads of English speaking schools in Thailand but these two are the biggest names. Ruam Rudee is another big name sorry.

Your kids will pick up Thai faster than you!

Every expat I know that lives in Bangkok, except for one Australian friend, send their kid(s) to an international school, myself included. There are international schools here that teach in most of the major languages around the world, English, French, German, Japanese, Chinese etc., with English being the most common. Not only would it be difficult for a non-Thai speaking kid to attend a Thai school, it would be next to impossible mostly because of language difficulties. Most teachers in Thai public schools aren't fluent in other languages. I also don't believe children of expats are eligible to attend Thai schools, unless one of the parents is of Thai nationality or the expat has acquired Thai citizenship, although I'm not sure exactly what the requirements are. There is one public school that I know of that does have an English/Thai bi-lingual program, the school my Australian friend and his Thai wife send their kids to.

http://www.udomsuksa.ac.th/english/

International schools where they teach English as a first language in the schools. If the schools have decent numbers of expat kids who cannot speak Thai. It should not be any problems or any difficulties to make friends or communicate with other kids because they will speak English to one another :).