Yes, we strongly recommend buying comprehensive travel insurance before visiting Koh Samui or other parts of Thailand.
You cannot get insurance to cover every possible event, however you can buy a solid, comprehensive policy that protects you against a wide variety of situations. The minimum cover we recommend is a policy that includes medical and health cover, personal liability, cancellation, and lost or stolen baggage and possessions. If you’re planning to take part in adventurous sports or any high-risk activities you may require extra cover.