Than Bokkharani National Park is located in Krabi Province about 45 kilometers (28 miles) northwest of Krabi Town. The park covers an area of 121 square kilometers (47 square miles) and is characterized by a series of limestone outcrops; evergreen rainforest; mangrove forest; peat swamp; and many islands. There are also numerous caves and cave complexes with some spectacular stalagmites and stalactites.

Than Bokkharani centers on two well known caves; Tham Lot and Tham Phi Hua; situated in an area of great tranquility and natural beauty; with surrounding streams; cascades and still; silent pools.

Tham Lot is a cave complex of winding passages filled with both stalactites and stalagmites that can best be reached by boat from Ao Luk's Bho Tho pier. Nearby Tham Hua Kalok is similarly reached by boat from the Bho Tho pier; and is best known for the ancient cave paintings - some authorities consider they may be more than two millennia old - that feature in places on the cave walls. In all; there are around 70 petroglyphs or cave paintings; portraying ancient peoples and animals.

Other well-known caves in the area's limestone mountains include Tham Sa Yuan Thong; which features a natural spring; Tham Phet or 鈥榙iamond cave' which derives its name from the shimmering rock walls; and Tham Song Phi Nong; which was found to contain skeletal remains of human beings; ancient pottery; bronze tools and earrings.

As well as caves; the park is a great place to explore mangrove swamps by boat - they are virtually impassable on foot; except in places where a boardwalk has been constructed. The park headquarters is set amidst a series of small streams and dark green pools; and is a popular picnic spot; it's also possible to camp here by arrangement with the park authorities.