Not as impressive as Sai Yok Yai waterfall further north and nowhere near as spectacular as Erawan waterfall, Sai Yok Noi is a tourist trap that's so regularly visited only due to its convenience.
It's located immediately off Route 323 around 45 kilometres west of Kanchanaburi. It's also a short walk from Nam Tok rail station, which is the final stop on the Death Railway train ride. To be fair, the falls do cascade elegantly off a limestone head, but the concrete walls that have been added to the natural pool ruin some of the atmosphere.
While here, check out the war-era locomotive at the very end of what remains of the Death Railway track, and pick up locally grown tamarind from one of the many vendors.
If you want to get away from the crowds, take the trail that leads up the mountain from near the waterfall and winds for 1.5 kilometres through a bamboo forest before reaching Wang Badon Cave. The cave has a very narrow opening, but broadens out into substantial chambers inside -- you will need a torch.
How to get there
Signs for the falls are well posted along route 323 and it's easy to find on your own. If you are heading to Sangkhlaburi by bus, it's likely you'll stop here for 15 minutes, which should be enough time to run over, have a splash and take a pic. Just clear it with the bus driver first!