How early can I apply for a Non-O visa extension based on marriage to a Thai, and when will it expire?

okay folks the O/P was NOT stamped in wrong, BUT you sure had to LOOK at the stamp carefully to see that they were stamped in for 89 days 😛

They did mark his visa out and stamp used, AND they did put the NON on the top of the red entry stamp

BUT

look how easy it would be to overlook the 3 in the 31 May stamp

Check No.18-STAYING WITH THAI WIFE from the link you mentioned.

𝗤𝟭 𝗛𝗼𝘄 𝗲𝗮𝗿𝗹𝘆 𝗰𝗮𝗻 𝗜 𝗮𝗽𝗽𝗹𝘆? <- You can apply for a yearly extension based on marriage to a thai in Bangkok when you have 45 days or less left on your current stamp.

𝗤𝟮 𝗛𝗼𝘄 𝗺𝘂𝗰𝗵 𝘁𝗶𝗺𝗲 𝗯𝗲𝗳𝗼𝗿𝗲 𝗲𝘅𝗽𝗶𝗿𝗮𝘁𝗶𝗼𝗻? <- you can apply right up until the last day you are stamped in for BUT we don't advise that because you don't lose any time applying early your new year extension is added to the current expiration date you have

𝗤𝟯 𝗠𝘆 𝘄𝗶𝗳𝗲 𝘀𝗮𝘆𝘀 𝘁𝗵𝗲𝗿𝗲 𝗮𝗿𝗲 𝗺𝗮𝗻𝘆 𝗵𝗼𝗹𝗶𝗱𝗮𝘆𝘀 𝗶𝗻 𝗔𝗽𝗿𝗶𝗹, 𝘄𝗼𝘂𝗹𝗱 𝘆𝗼𝘂 𝗽𝗹𝗲𝗮𝘀𝗲 𝘁𝗲𝗹𝗹 𝗺𝗲 𝗼𝗳 𝗮𝗻𝘆 𝗯𝗲𝗳𝗼𝗿𝗲 𝘁𝗵𝗲 𝟭𝟱𝘁𝗵? <- Like always government offices are closed during the Songkran holidays (this year that will be April 13-14 & the 17th too 😮 plus they are also closed April 6th for Chakri Day)