What should I do if my visa and my son's visa expire before my bank deposit is three months old in Thailand?

As the funds will not be seasoned for the required 3 months (have you checked that your Immigration Office that they require 3 calendar months not 90 days?) will they allow you to apply for a new Non_O which only requires seasoning of 30 days?

I had a similar situation to you last December, my B400k would be 2 months in the bank on the same day my extension (non O Thai wife) was due. I went in to the office weeks in advance to talk to them. They told me that I could not get the extn until the following day which would make me one day everstay. The IO advised that I could get a short term extn - visit family - or go OS. His advice was OS 1 day and keep the family visit for any emergency in the future. He said I could only get one per visa.

This was in the Kanchanaburi office, probably different wherever you are, so go in and have a chat

It's Thailand. It's down yo how the immigration officer feels on the day. He may have had a row with his wife that morning .!! Stick to the rules. Don't try to break the rules. You are a guest in their country. The least you can do is respect their laws. The law is quite clear.

Put U in prison,plenty of pickels.

Never overstay, it may come back to haunt you some day.

Solve the problem, before it gets to be a problem, and go to Immigration and discuss it with them several days before the visa expires.

This happened to my friend earlier this and they just fined him 500 baht one day overstay but as others have said go to your local office and ask. Curious as to what extension you think requires 500k

Just a thought. Is this your first application for the year “guardian” extension?

Go talk to them facebook can't give you a visa only immigration can

Tell your home bank to make the deposit a few days earlier…..

Go now get an extension. Assume you are converting from tourist to a long stay.

That’s going to be office specific. Go there and ask them.