Visa transfer to new passport?

[sjbrownderby]

I am currently on a multi entry spouse visa, issued in Savannakhet. It is due to expire in May and I have 5 clear pages in my passport, which I will have to renew sometime within the next year. I am not sure whether to renew my passport (doesn't expire until 2024) before or after I go again to Savannakhet. Either way I will have to have the visa transferred to the new passport. Has anyone done this before? Is it possible to transfer the visa from one passport to the other?

 The Non-O multi entry spouse visa means a border crossing every 90 days and at least one page of my passport taken up with a visa, plus stamps,  each time. I intend to apply for a passport with more pages this time and within the next few years I will change my visa so I will not have to do a border crossing every 90 days. 

[ubonjoe]

A visa cannot be transferred. You would use both passports on entry until the visa expires to use the still valid visa in your old passport and get the 90 entry stamped in your new passport.

If you get a extension of stay at immigration it can be transferred to your new passport.

[sjbrownderby]

Thanks, ubonjoe, I was concerned that the visa might be invalidated if I started to use a new passport without notifying immigration.