Drought has forced the closure of accommodations at well-known Phu Hin Rong Kla National Park straddling Phitsanulok, Loei and Phetchabun provinces from April 1, according to park chief Suwan Phanunampha.
Mr Suwan said drought has become more serious, causing water sources across the park to dry up.
The water shortage, coupled with the start of low season, prompted park officials to ask the National Parks, Wildlife and Plant Conservation Department to allow them to halt bookings for living quarters inside the park, fearing there won't be enough water for visitors.
However, the park has no objection to tourists bringing their own water and tents for camping.
Moreover, the park is considering stopping supplying water to some 100 resorts and hotels at Phu Thap Boek to reserve it for several local communities.
Those resorts and hotels have been informed so they can arrange their own water, such as by drilling artesian wells. The inns will get up to a month's notice before the water is cut off.
Phu Hin Rong Kla is generally dominated by mountainous terrain. Many spots have become most popular with tourists, particularly Phu Thap Boek.
During the peak of Communist insurgency, Phu Hin Rong Kla was where several insurgent jungle strongholds were located. These locations today are major tourists attractions.