A british friend of mine bought a single entry tourist visa in London last october (enter before date on visa sticker is 8 january 2018). When she arrived in Thailand, Samui airport Immigration ignored her visa (did not stamp "Used" on it) and give her 30 day visa exempt stamp. My friend not only didn't realize that but, when her 30 days were expiring, she got a 30 day extension at Samui Immigration.
We think that, having on her passport a valid tourist visa, not used and not stamped, valid till 8th january 2018, she could do a border run and re-enter using her tourist visa and getting 60 day stamp.
But Satun officers and Samui Immigration said that - having extended her initial 30 day stamp by other 30 days - she made her visa useless and she cannot use it anymore.
Any experience about similar situations? Thanks
TLDR : Answer Summary
A British traveler encountered issues with her unused tourist visa when entering Thailand, as she received a 30-day visa-exempt stamp instead. After extending the initial stamp by another 30 days, local immigration claimed her unused tourist visa was now invalid. Community responses suggest that since the visa was never stamped as used, it should still be valid if she enters before its expiration date. Others shared similar experiences, emphasizing the importance of ensuring the visa number is correctly entered on arrival cards to avoid confusion.