HI GUYS I need some help. Although I had been in this airport, I have a little bit complex situation now. I have a Belgian citizenship so I of course do not need a visa on arrival but this time I am arriving from India with Air India express, I have couple of hours (2) to catch a flight to Sigapore by SWISS. I do not want to go thru the crowd in immigration and then do a check in from outside and com back in again (I may not have time for that even). I shall only have a handbag. Question is, can I check in to SWISS (which is a star alliance) from a inside transfer desk ??? Is that allowed ? This flight was bought separately and no connection with AI express. Can anybody advice me ?

That's why the transfer desk is there. Actually AI should be able to check in you luggage all the way to SIN and just check in to swiss at transfer desk to get boarding pass. Not done this with AI / Swiss myself but that's how it works with with others. Just did this couple of weeks ago with Thai and Malaysian.

yes if you have no hold baggage just head to transfer desks where you can transfer airside

have a good trip

Correct when you arrive at Bangkok go straight to one of the transfer desks (same level you arrive)

There are 2 (the main one for Thai and star alliance is at the junction of the A, B, C and D piers), they can get very crowded.