I have a Japanese friend coming to live here in a short time. After a couple of weeks he intends to go to the consulate in Vientiane Laos and get a non immigrant "O" Visa based on his marriage to a Thai citizen. Could someone please give me a list of all the documents he will need to get that one year non-immigrant "O" visa in Laos.

Once he has that he will report to Immigration at Mae Sot and I am sure that they will assist him with the rest. Thanks in advance for the help

The above post is talking about extensions of stay which are applied for and approved by immigration inside Thailand so not sure if this is what you want information on, or just the class O visa to be extended, or a one year multi entry class O visa which you apply for and receive outside Thailand (and for which Vientiane is not the best place to apply). But if he intends to extend inside Thailand he only needs a single entry non immigrant visa anyhow; although some have claimed even that is resisted by Vientiane (I would advise calling them direct just before travel to make sure he has what they want). It may be a long trip but Penang is usually the best choice.