For those climbing Cadair Idris via the Minffordd path on the mountain's southern side, Llyn Cau comes into view at a height of 1550 feet. It's a very picturesque oligotrophic lake just a short distance off the path and is a good place to stop for a break or a quick dip. There's a small stony beach on the south side, and on a summer's day the water is an enticing deep blue. The depth at the centre is estimated at about 150 feet.