Can I extend my 90-day visa exempt entry by 30 days in Chiang Mai?

The user inquires if they can extend their 90-day visa exempt entry for another 30 days at the immigration office in Chiang Mai. Comments from other users provide insights into extension possibilities, noting that as a Korean national, they may only be eligible for a 15-day extension rather than the requested 30 days. Some users recommend checking the specific visa type and stamp to determine extension eligibility, with suggestions to potentially exit and re-enter the country for a new 90-day exemption.