Where do most expats live and why ?

After 15 years in Thailand I want a change.

I too used to live in Thailand. Most live in District 1, 2 or 7.  It very much depends on the lifestyle you are looking for and your budget.  Myself, I swapped a downtown condo for house overlooking a small park in a rediential complex.

Thanks. I like living on the coast, Pattaya for 15 years.

In Saigon? Districts, 1, 2, 4, 7 and Binh Thanh district are generally considered the most comfortable/convenient for expats.

Anywhere, where there are plenty of expats , bars and fairly easy to get around as I don't plan on driving. Most popular coastal area for expats?

Nha Trang, Danang or Vung Tau probably most popular coastal places. Don't have experience with all of them, but most people seem to say the beaches are better at the first two I mentioned.