Khao Sam Roi Yot National Park

Khao Sam Roi Yot National Park is a coastal protected area in Prachuap Khiri Khan, Thailand, that encompasses limestone mountains, caves, beaches, wetlands, and mangrove forests. The mountain range runs parallel to the Gulf of Thailand shoreline and creates a landscape of jagged peaks, saltwater ponds, and sandy coves.

The Thai government declared this area the country's first coastal national park in 1966 to protect mangroves and wetlands. King Rama V visited Phraya Nakhon Cave in the late 19th century, and a royal pavilion was later built inside to mark the occasion.

The name means "mountain with three hundred peaks" and refers to the many limestone formations rising from the coastal plain. Fishermen still use wooden boats near the shore, and the wetlands support flocks of wading birds that arrive with the changing seasons.

The park sits about four hours south of Bangkok via Highway 4 and can be reached by car or hired vehicle. Many caves and viewpoints require short walks over uneven paths, so sturdy footwear is recommended.

Phraya Nakhon Cave receives natural light through an opening in its ceiling at certain times of day, illuminating the royal pavilion inside. The best time to see this light effect is in the morning between late January and April.