The 958-sq-km Sai Yok National Park is home to limestone mountains, waterfalls, caves and some extremely rare animals. The best-known attraction is Nam Tok Sai Yok Yai (Sai Yok Yai Waterfall), where a stream makes a short drop into the Mae Nam Khwae Noi river. The bigger Nam Tok Sai Yok Lek is on the other side of suspension bridge. Both are small, but beautiful because of how they flow out of the forest.
Because there are numerous sights right around the visitor center, along well-marked and maintained trails (most open to bikes), it's easy to explore the park independently. And it never gets nearly as crowded as Erawan. Other destinations right near the falls are a natural spring , riverside viewpoints , old Japanese soldiers' stoves , and long-tail boat hire (400B per half-hour).
The world's smallest mammal (3cm long), the very rare Kitti's hog-nosed bat, was first spotted here in 1973. They hang out, literally, at Tham Kang Kao ('Bat Cave'), 2km from the visitor center, along with many regular-sized bats. Take a torch. Along the walk to Bat Cave you can take a short detour to the foundation of a Death Railway bridge. Just past the bridge, keep your eyes peeled for an unmarked original stretch of the track.
Another animal species discovered at Sai Yok (in 1983) is the red, white and blue Rachinee crab, but you're unlikely to see it. Nor will you likely encounter any elephants, gaurs, tapirs or sambar deer, since big animals prefer the remote western side of the park. You might, however, see barking deer and water monitors near the bridge.
Beautiful Tham Doawadueng cave is rich with both rock formations and animals; bats, crickets and snakes. There are lights, but not stairs, so the entrance can be treacherous when wet. A ranger will accompany you in, and though it's not required, a tip is deserved. Bats stream out just before sunset, except during the hot season. It's 6km northwest of the park entrance by road, or you can hire a boat for 1000B return, but you'll have a 1.5km uphill walk to the cave.
There are park bungalows and a campground (tent hire 270B), but the raft resorts around the bridge, including the clean and comfortable Krit Raft House and @Raft , are a better choice. There are also floating restaurants plus many food stalls at the parking area.
The visitor center is 95km northwest of Kanchanaburi. Sangkhlaburi–Kanchanaburi buses (60B, 90min) pass the turn-off to the park. The visitor center is 3km off the highway. Motorcycle taxis (20B) wait near, but not right at the junction. When leaving the park, the visitor center can call them. The last bus back to Kanchanaburi passes around 5pm.
