Thailand's biggest national park is not Khao Yai.
The largest park is actually Kaeng Krachan National Park (2,915 square km) and it stretches along the Tanaosi Range (part of Thailand's border with Myanmar) in the Petchaburi and Prachuap Khiri Khan provinces. It is the origin of two large rivers (Petchaburi & Pranburi), two dams/reservoirs (Kaeng Krachan & Pranburi), is host to large stretches of forest and has an impressive biodiversity.
In fact, 80% of the park area is covered in dense forest and the park is considered very important for wildlife conservation.
Activities in the park include trekking, bird watching, sailing/fishing, rafting, butterfly watching, and off-road driving. Most tracks (nature trails) require more than one day to complete, so first-timers should be accompanied by a park ranger. Butterfly watching is best in the dry season and preferably along the Wang Won - Phanoen Thung route.
The most popular nature trail is roughly 40 km long from Wang Won to Namtok Tho Thip. At km 30, you can detour to climb Khao Phanoen Thung - at 1,200 meters, it is the highest peak in the park.
The national park provides lodges and tents in case you don't bring you own tent or in case you don't prefer more luxurious accommodation in the resorts near the park.
