Thailand's oldest national park and UNESCO World Heritage Site, 2.5 hours from Bangkok — waterfalls, elephants, gibbons.
Khao Yai is Thailand's most visited national park — 2,000 km² of forest with waterfalls (Haew Narok is spectacular), wild elephants, hornbills, gibbons, and tigers (rarely seen).
Organised tour from Bangkok best (3,000–5,000 THB including transport, guide, lunch); self-drive possible with rental car; public transport is very slow.
Early morning wildlife walk, waterfall hike (some swimming holes), night safari (bats, deer, owls).
Several lodges inside or near the park; staying overnight dramatically improves wildlife viewing — animals move at dawn and dusk.
Sturdy shoes, insect repellent, a light rain jacket even in dry season, and binoculars if serious about spotting wildlife from a distance.
November to February offers cooler, drier weather and the clearest visibility; the rainy season (June–October) brings lush scenery but muddier trails and fewer wildlife sightings.
A knowledgeable local guide dramatically improves wildlife spotting odds — most day tours include one, and it's worth confirming this specifically when booking independently.