Can I enter Thailand on a 30-day visa exemption and extend it for a total of four months with border runs?

Yes, you can enter Thailand on a 30-day visa exemption stamp, which can be extended for an additional 30 days at an immigration office. Following this, you can perform one land border run to gain another 30-day stamp, allowing for a total stay of up to four months. However, be aware that airlines may require proof of an outbound ticket when you check in. It is also important to consider the risks involved, as entry on border runs can sometimes be denied.