Whether or not you are changing terminals doesn't matter. People arriving are never in the same area as people departing, and are forced to a certain direction. You cannot just go from one flight to another in the international terminal. You will have to either go through the international transfers desk if you have a single itinerary/ticket you are flying on, or you will have to go through passport control and enter Thailand and then check-in for your next flight if you are flying on different tickets and doing a self transfer.

If the 2nd one is the case, then whether or not you need a visa is completely dependent upon which passport you hold, which you did not include in your post.

@Fatih *******

You've purchased a special VIP entry package FROM AN AGENT many times? Or you purchased and used fast track many times? They are not the same thing at all.

@Edna ******

An ED visa would be even more reason to be denied entry. You are not supposed to leave the country if you have an ED visa, you are supposed to be in Thailand studying. A ton of people get denied entry for leaving and trying to return while they are on ED.

@David ******

This is not normal Fast Track, this is VIP entry from an agent. Someone will be standing at the jet bridge with your name on it when you get off the plane. They will walk you to the VIP area of the passport control and they will tell you which line to get in because it's all been previously arranged.

@Fatih *******

You absolutely have help when you use a service like this. This is not Fast Track, this is VIP entry service from an agent.

Either send him to Vientiene and have him cross by land at Nong Khai, or fly back to to Bangkok and use a VIP entry service with an agent like this

@Leo *********

The law says 24 hours. But immigration has no way of knowing when you actually arrived. As long as you have an updated TM30 before you go to immigration, you are unlikely to have any issues.

Avoid Cambodia as they just announced a 10 day wait. You can either apply in Laos with an appointment in person, or go to Vietnam as I've seen a good report of getting it in 2-3 days, but I forget which embassy it was in Vietnam through e-visa. Also Taipei has good reports but it's a little bit further out.

This is not from any personal experience I have, but from reading many posts on the subject.

1) Wait until you are in Thailand so you can oversee and check, and check constantly if not be seen on the site every day.

2) Do not pay upfront. Set very specific waypoint steps in the contract. For example: Foundation is laid and walls are up, receive 25% of the pay. Roof goes on, receive the next 25%, etc. You can pay upfront for the materials or even order them yourself, but do not pay everything up front, and do not listen to any sob stories or excuses about why they need the money before finishing a certain point, as it's in the contract. This is how people end up with a half built house after paying for the entire project. It's their job to figure it out because they agreed to it in the contract.

There are 3 embassies in Malaysia, and they've all just switched to e-visa, so you will have to select one you want to apply through.