I am now on a Non-Imm-O visa issued on 26.3.2015, with an entry stamp from 1.4.2015, until 28.6.2015.

I have two questions regarding the Extension of stay application requirements:

1. When should I apply?

2. We live in a rented condo in Bangkok. My wife is from Korat and the original Tabien Baan is there, around 7 hour trip from here. Do we have to bring this original when submitting the application?

1. Bangkok immigration allows you to apply up to 45 days before your permit to stay ends (June 28th).

2. You just need a copy of the house book. The page that shows the address and the page she is on.

You will also need proof of residence for where you living. They will want a copy of the rental agreement with signed copies of the owners house book and ID card attached.

To make sure I understand your answer - should I apply before I reach the last 45 days of my permit to stay, or can I apply starting from that period?

You can apply from 45 day before all the way up to the last day.

To make sure I understand your answer - should I apply before I reach the last 45 days of my permit to stay, or can I apply starting from that period?

The earlier you apply the better. You can apply from 45 days before the end of your permit to stay all the way up to the end of your permit to stay. You lose nothing by applying early (the new extension will start when your current permission ends, not the date of your application). Leaving it till the last minute doesn't put you in a good position to handle any complications that may arise.

You also need to have proof that your money has been in the bank for more than 2 months.

pictures of you and your wife in front of your apartment with the address visible in the picture.

A copy of your marriage license and sometimes they ask for another paper k3 (I forget) from local amphur that states you both had the right to get married.

You can apply for the extension 30 days prior to it expiring at all immigration offices or as ubonjoe stated in BKK they allow even more time. Which for you would mean that you could go anytime after the 15th of may. I normally do about 3 weeks before the deadline.

good luck

Great, thank you for the quick answers. I will try to arrange all those documents during the next days and apply next week.