The largest of the five crater lakes and the one the town is named after. It sits in a deep, near-circular caldera around 350 metres across, with steep wooded slopes dropping straight down to the water. The water is dark, clean, and warm.
The lake is ringed by hotels and lodges, the older Bishoftu Lake Resort being the longest-established. Boat trips and pedalos can be hired from the eastern shore. The cliffs on the southern side are the best place to take a photograph of the lake; the road from Addis comes in just above them.