How long does the 30-day visa extension process take at the Chiang Mai immigration office?

The process for a 30-day visa extension at the Chiang Mai immigration office typically takes about 3 hours on a less busy day, according to one user. However, it can take all day if the office is crowded, so arriving early in the morning is advised. It’s also worth noting that external factors, such as flooding, may affect access to the immigration office.