Pang Sida National Park

Pang Sida National Park covers 844 square kilometres of forest in Sa Kaeo province, about 27 kilometres from Sa Kaeo town, and forms one piece of the Dong Phayayen-Khao Yai Forest Complex — a UNESCO World Heritage stretch of contiguous forest running from Khao Yai National Park to the Cambodian border, alongside Thap Lan and Ta Phraya national parks and the Dong Yai Wildlife Sanctuary. Entry is 200 THB for foreign adults (100 THB children), 40 THB for Thai adults (20 THB children), plus a 30 THB vehicle fee, and the gate is open daily 08:30-16:30.

The park’s calling card is butterflies — over 400 species have been recorded here, likely the highest count of any national park in Thailand. Sa Kaeo province runs a butterfly-watching season from May to July, though the biggest gatherings, hundreds or thousands clustered on mineral-rich mud along the streams, tend to show up in the wet season around August. Waterfalls are the other main draw: Pang Sida Waterfall itself, a 10-metre drop about 1.7 kilometres from park headquarters, is the easiest to reach, while Namtok Pha Takien lies a further 2.4-kilometre trail beyond it. Both run fuller in the rainy season and thin out by the hot months. Ancient dipterocarp trees tower over the trails between them, and the forest holds around 150 recorded bird species, plus gaur, elephants, dholes, and marbled cats — tigers are on the park’s species list too, though sightings are rare and most visitors’ evidence of them is tracks rather than a direct encounter.

Watch out: Facilities beyond the headquarters area are basic — a few marked trails and a campground, little else. Mobile signal drops out through most of the forest, so download offline maps and tell someone your planned route before setting off on the longer trails.

Cool-season months (November-February) give the most comfortable hiking conditions, though they miss the butterfly peak. Pack insect repellent, proper hiking shoes, and enough water — there’s limited resupply once you’re past the visitor centre. Overnight camping is an option for dawn and dusk wildlife activity, when animals are more active near the waterways. For another national park on the same UNESCO forest complex a short drive away, see Ta Phraya National Park, which adds prehistoric cave paintings to the mix.