🔄 Updated 21 Jun 2026
Wiang Kosai straddles the border between Phrae and Lampang, but the side most people enter from is Wang Chin district in Phrae, because the park headquarters and Mae Koeng Luang Waterfall sit on this side. The draw here is the dense green forest, air that stays cool even in the hot season, and waterfalls that run hard from late rainy season into early winter. It's a place locals and nature-minded hikers visit quietly — still nowhere near as crowded as the famous waterfalls in central Thailand.
Mae Koeng Luang Waterfall — the park's headliner
Mae Koeng Luang is the main waterfall most people come specifically for. It's a rock-tier waterfall dropping through roughly 7 levels, stretching about 200 metres from the top tier down to the bottom, with a clear pool at each level you can wade into. The water is icy cold because it flows down from headwaters deep in the forest. The lower tiers are an easy walk from the parking area, while the upper tiers take a bit of rock-scrambling. People after a good photo usually climb up to the middle tier, where the falls are wide and there are boulders to sit on.
What to know before you go
Mae Koeng Luang Waterfall is closed from 1 July to 31 October every year, because that's the peak of the rainy season — the water surges hard and the rocks get dangerously slippery. If you're set on swimming at this waterfall, steer clear of those months. The best window is November to February: there's still plenty of water from the rains, but it flows calmly and is far safer.
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Mae Koeng Noi Waterfall — for the real hikers
If Mae Koeng Luang is the waterfall for everyone, Mae Koeng Noi is for those who actually want to hike. You walk in from the park headquarters for about 2 kilometres, through humid green forest, past streams, with birdsong the whole way. The round trip takes around half a day. At the end is a small, peaceful waterfall with far fewer people than Mae Koeng Luang — ideal if you're after quiet and a genuine forest feel.
- Get ready — wear shoes with grip; the trail has rocks and tree roots, and the ground gets muddy in the rainy season
- Water — bring enough of your own; there are no shops along the way
- Timing — set off in the morning so you're back before the light fades; don't start too late, as the forest gets dark fast
Mae Jok hot spring — a warm soak in the forest
Another spot a lot of people don't know about is the Mae Jok hot spring, a natural hot spring inside the park. The temperature is comfortably warm — good for soaking your feet or your whole body to ease the aches after a full day of hiking. It's a perfect contrast to Mae Koeng's cold falls: play in the cold waterfall during the day, then come soak in the warm spring in the evening, and your body fully unwinds.
Swim at Mae Koeng Luang Waterfall
Clear, cold water; the lower tiers are an easy walk and good for families, with boulders to rest on
Hike to Mae Koeng Noi Waterfall
A 2 km trail through dense forest — few people, peaceful and quiet, made for hikers
Soak at Mae Jok hot spring
A natural hot spring to ease the aches after a hike; warm at just the right temperature
Camping in the forest
The highlight of coming to Wiang Kosai is staying overnight. The park has two campground zones — one at the park headquarters and one at the youth-camp area. The night atmosphere is genuinely quiet, and the air is cold, especially in winter when some nights drop below 15°C. If you don't have gear, the park rents out tents (roughly 3-person size), and there are park bungalows for anyone who doesn't want to sleep in a tent. There are shared bathrooms and a simple restaurant at the headquarters.
- Park entry fee — around 200 THB for adults, around 100 THB for children (charged once per visit)
- Camping / tent rental — you can pitch your own tent or rent one from the park; ask at the headquarters first, as prices change by season
- Park bungalows — book ahead through the Department of National Parks' accommodation system; they fill up fast in winter
- Pack for the cold — a sleeping bag, a warm jacket, and a flashlight are essential in winter
Book ahead — it's worth it
Winter (Nov–Jan) is the peak season, when people flock here to camp in the cool air. The campground and bungalows fill up very fast on long weekends. We'd recommend calling the park headquarters first (tel. 081 030 8663 / 093 272 7806) or booking a bungalow through the Department of National Parks website in advance. Don't just drive out without checking — Wang Chin is far, and there isn't much accommodation in the surrounding area.
Getting to Wiang Kosai
The park is in Wang Chin district, southwest of Phrae town. Driving yourself is by far the most convenient option, as public transport barely reaches it. From Phrae town, take the route through Long district out to Highway 11 (the Lampang–Den Chai road), then head toward Wang Chin. When you see the park sign on the side of Highway 11, turn in and drive about 1 more kilometre to the headquarters. From Phrae town, the total trip takes around 1.5–2 hours depending on the route you choose.
- Private car — the most convenient; the final stretch is a winding mountain road, so check your brakes and tyres before you go
- In the rainy season — some sections get slippery and there can be landslides, so drive with extra care
- Fuel up — fill the tank in town before entering the park, as there are no petrol stations inside
An overnight plan for Wiang Kosai
Into the forest, swim the falls, pitch the tent
Hike Mae Koeng Noi, then head back
Pack and prepare
- Warm jacket + sleeping bag — winter nights get very cold; don't underestimate it
- Hiking shoes — the trail has rocks, tree roots, and slippery ground
- Mosquito repellent + first-aid kit — there are plenty of mosquitoes in the forest in the evening
- Supplies and drinking water — shops in the park are limited, so stock up in town
- Trash bags — pack your rubbish out and help keep the forest beautiful
Plan your whole Phrae trip, from the old town to the forested hills
See the Phrae travel guide →