What are the current requirements for traveling domestically within Thailand, specifically from Phuket to Ko Samui?

Traveling within Thailand, including from Phuket to Ko Samui, generally does not require stringent measures. While proof of vaccination may be asked for in some cases, many travelers report that showing a vaccine certificate is sufficient where required. Each province may have different regulations; for instance, while traveling between Khon Kaen and Bangkok has mentioned requirements like vaccination or a negative test, overall travel appears more lenient, especially via taxi and ferry.