The famous Rainbow Fall (Air Terjun Pelangi) can be reached from Sg Lembing. In earlier days this small town was famous because of its tin mines. Now it is nice, sleepy place. There is a museum and there are plans to reopen the mines as a tourist attraction. Transport to the fall can be arranged in the town, you need a 4WD if you want to go on your own. A guide is useful, although not really needed. You have to start early, as the famous rainbow can only be seen in the morning. It is a one hour drive from the town to the trail head, followed by about 45 minutes of easy trekking to the fall.
The road to the trail head is a nice one, condition is good in general, with some difficult stretches, depending on the season. Beautiful views of the Kuantan river. Halfway you will pass a resort, might be a nice place to stay overnight, but it was closed and nobody could give us more info.
After about 20 km you reach the end of the road, where the trail starts with a river crossing. The trail is very well signposted and brings you in about 45 to the waterfall.
The waterfall itself is not spectacular, unless after heavy rainfall. It is a tall fall, and under normal conditions the water comes down as a spray. It is this spray which results in the famous rainbow, but only when the sun is still low.
In general you will not be the only visitor here, and there will be a lot of oh's and ah's, when the sun breaks through the clouds. It really is a beautiful experience. If you are lucky, you can even see the double rainbow.
There are more waterfalls in this region, but we had no time to explore.