Can I use ADAC Auslandskrankenversicherung Longstay for my visa application's healthcare insurance requirement?

Yes, you can use the ADAC Auslandskrankenversicherung Longstay for your visa application, but you must first download the additional insurance form from Immigration and ensure ADAC fills it out and provides an official stamp confirming their liability. This document will need translation and legalization, which might complicate things, so it may be simpler to consider a policy from a nominated Thai insurance company instead.