Huai To - upper fallsHuai To- park

The park is about 30 minute drive from Ao Nang Beach or Krabi town.  You will pay about 100 baht ($3) per person for entry.  The area is very pretty with giant trees near the parking area.  They have a small shops with food there and nice grounds.  There are two routes to the waterfall one easy and one more challenging and steep.  If you take the long route there and back it is a bit strenuous.  The hike is about 35 minutes if you're in shape.  Recommended this for younger and stronger hikers. Also wear something more than flip flops.

The waterfall has an upper (20 ft) and lower (50 ft) section. The upper has a nice pool for swimming.  It might be a good to take the long way up and shorter route down.  This way you can see both sections and have a restful return.  Half day for the entire trip including driving would be more than enough time.