Do people teach on tourist visas for a long time? Why?
Yes, some people do teach on tourist visas in Thailand - though it's technically illegal. This usually happens when schools are unwilling or unable to sponsor a work permit, or when teachers are in the country temporarily and want to earn money without going through the full legal process.
Some teachers may also accept jobs on tourist visas while waiting for their paperwork (like the Non-Immigrant B visa or work permit) to be processed. Others may work this way knowingly, often for small language centers or schools that operate under the radar.
While it might seem convenient, teaching on a tourist visa is risky. If caught, both the teacher and the employer could face fines, deportation, or even blacklisting. Immigration enforcement in Thailand has become stricter in recent years, so relying on this approach long-term is not advisable.