What Are the Options for Long-Term Stay in Thailand for South Korean Passport Holders?

and I think this is just going around in circles. Good Luck to the O/P and their children.

Get the right visa for your stay. You're not married, but have children. I'm assuming they are NOT half-Thai.

1. Are your children studying in Thailand at a Thai school? If they are, then they should get an ED visa. You, as their mother, can get a Non-O to stay with them.

2. Do you have a job in Thailand? If you do, you can get a Non-B visa.

3. If you and your "partner" feel comfortable, marry him, and get a trailing spouse visa.

4. Getting an elite visa is an option (assuming you don't have any overstays).

What's the cutoff point between "tourist" and "living here on a tourist visa"? It's whatever the immigration officer believes. If you're having to ask yourself "am I a tourist", you probably aren't. This isn't America, where you can look at a calendar and there's a firm cutoff from "tourist" and "living here".

Get your children on an international school with the Non Immigrant ED visa and you can get the Non Immigrant O visa based on being their parent, OR get the Non Immigrant B visa and Work Permit so you can work legal inside Thailand. Or go for the Thai Elite VIsa, there are different options to stay long time on a better visa

Not sure if your excuse is what you really did, but sending your children on a different flight and hoping that you can use this as excuse to avoid being denied entry, seems to me you are well known of the risks you take with abusing the system. I would say, if your kids story is true, stop with this kind of activities and get yourself and your children legal in Thailand or choose another place where you can live a legal life.

a Very good question as there is no definition of what is a tourist. The only thing what comes back in every description of a tourist is a person who leaves the residency for pleasure, culture or what ever, And seeing you are living inside Bangkok, the Immigration Officers do not really believe you are a tourist.

you may just ask the question, many times people do remember certain things or even use the search option to find what you are looking for