Khao Sam Roi Yot means "mountain with 300 peaks.[1] The limestone hills are a subrange of the Tenasserim Hills that arise at the shore of the Gulf of Thailand, with the highest elevation being Khao Krachom at 605 m. Between the hills are freshwater marshes. Several of these marshes were converted into shrimp farms, as only 36 km² of the total 69 km² of marshes are part of the national park. A portion, 18 km², of these marshes are scheduled to be declared a Ramsar site.
Two white sand beaches are in the park, Hat Laem Sala and Hat Sam Phraya. Hat Laem Sala is 17 km from park headquarters and can be reached from the village Ban Pu either by boat or by climbing up and down over a hill for nearly 30 minutes.