I read on a visa agent website that you had to have 18 months left of eligibility in your passport to get a one year extension based on marriage. Did not see this anywhere else so just wanted to check to see if this is correct or not (hopefully not correct).

Not heard that one before, but you DO need to be valid past the end date of your potential extension.

 

That makes sense.  You need 12 months for the extension and another 6 months so you can enter another country (besides your passport country).  Most countries will not allow entrance unless a passport is valid for 6 or more months. 

 

The Thai Embassy in Washington, DC requires a passport be valid for at least 18 months in order to receive a 1-year OA visa.

 

https://thaiembdc.org/consular-services/non-immigrant-visas/non-immigrant-category-oa/

Probably confusion between a one year multiple entry visa from an embassy or consulate that does require 18 months of passport validity and a extension of stay issued by immigration.

There is no minimum passport valid to apply for any extension of stay.

If you do not have 12 months of passport validity the extension will only be issued to the date your passport expires. 

Just now, SEtonal said:

That makes sense.  You need 12 months for the extension and another 6 months so you can enter another country (besides your passport country).  Most countries will not allow entrance unless a passport is valid for 6 or more months. 

There is no such requirement to apply for an extension of stay. 

It is only for certain visas to be issued at an embassy or consulate.

Just now, ubonjoe said:

There is no such requirement to apply for an extension of stay. 

It is only for certain visas to be issued at an embassy or consulate.

Thanks.