I have 2 multi non immigrant O visas in my passport.

The first expired on the 10th October and the second is valid from September 15th 07 to the same date next year.

I arrived on Oct 2nd and on my arrival card I put the visa number of the second visa but the immigration officer crossed it out and admitted me on the basis of the first visa.

1. Just checking that I dont have to activate the 2nd visa within a time limit of 90 days like the tourist visa or anything like that, right?

2. When I got the 2nd visa I hadn't heard of the rule that marriage visas could be extended for 2 months by going down to immigration with marriage documents. I am only here until the end of Feb (i.e. within 2 months of initial expiry) and a 1900 Bt extension would be cheaper than leaving the country to activate my 2nd visa.

Is this possible with the multi entry visa I have got?

What documents do I need to take?

What is the absolute earliest I could go to immigration to get this extension for peace of mind?

Because if they refused (maybe they will say just go and activate your unused visa at a border) I would be stuck with getting an immediate epensive christmas flight to a nearby country. (I really hate land border turn arounds)

P.S the first visa i.e. the one that I would be extending was not obtained on basis of marriage. It was visiting girlfriend.

The second visa (not activated yet) was obtained on basis of marriage.

Could this be a potential problem?

Thanks

1. You can enter any time during the validity of any visa - there is no "activation". So you do not have a problem with visa.

2. I suspect immigration will be less than happy to provide the extension of stay (which is a special provision and only can be used one time) while you have a valid visa for entry but only asking can tell for sure. But now you are asking the earliest you can do it and making it even more out of the ordinary. I would guess 4 week or 30 days would be the earliest they would consider it but again only asking will get a real answer as these type decisions are often based on officer/situation rather than any fixed rule.