From Aparthotel Boquete, turn right on Central Avenue towards Los Naranjos. The road forks in Los Naranjos, there turn right and follow this road without diverting.
After about 100 m you will see a rock wall on the left, which is often used to exercise climbing. This rock is called "Los Ladrillos".
Shortly afterwards, the road crosses a bridge over the Caldera River. Follow the road, with the river remaining on your left. After a few kilometers, the road crosses the river again after a left turn.
Then, pay attention to the signs that announce "Bajo Mono Camping". You can park your vehicle there and continue your trip hiking.
Without a car:
If you don't want to walk all the way to "Bajo Mono Camping" (it's about 5 km mostly uphill), there are small buses going to "Bajo Mono", starting at the town center at the corner where you can see an unfinished 3 stores high building on the main road. The is the informal terminal for taxis and small busses that go in the direction of Los Naranjos.
The owners of the Bajo Mono campsite will show you how to walk to the waterfall.
From here you can reach also the other waterfalls (about 3 km or more from there, depending on where you go).
Continue on this path in the original direction. Finally, you reach another bend to the left, where the "Quetzales Trail" (Sendero de Los Quetzales) is distinguished. The quetzal is a particularly beautifully colored bird that lives in the humid highlands of Central America. It is quite shy, so you will need some luck to view one of them. Some of our guests told us that they have seen them on their trail.
Here turn right on a narrower paved road and continue until the end. There you park your vehicle and register with local forestry officials who will show you where to walk to reach the Lost Waterfall. Registering is necessary to avoid being lost in the vast forests and mountains.
You will certainly remember this trip for a long time.