Morpaeng Waterfall

Go for the water, not the walk. This is a multi-tiered cascade outside Pai with natural pools at the bottom of the drops, deep enough to swim in when the flow is good, and enough shade from the surrounding forest that you can sit out the middle of the day without cooking. It draws a mix of Thai families and travellers on rented scooters, which tells you it's easy enough to reach and worth the ride.

My advice is to come first thing, not long after the 08:30 opening. You get the pools mostly to yourself, the light is better through the trees, and you avoid the mid-afternoon crowd. The path in is uneven and gets genuinely slippery after rain, so leave the flip-flops behind and wear something with grip. Bring a change of clothes if you plan to get in, because there's nowhere to hide while you dry off.

Water levels swing hard with the season. After the rains it's powerful and the rocks are treacherous. Late in the dry months it can be a trickle.