From the Landsborough, follow Dechen Creek through the bush to reach the slopes and the icecap. The route leads to the ill-defined south ridge and on to the summit.

The extensive McCardell Glacier provides easy travel from the south side of the mountain to the summit.

The head of the Otoko Valley provides access to the western slopes of Dechen via the McCardell Glacier. The first ascent commenced from near the former Lake Otoko. The lake has subsequently been filled by landslide. Mt Dechen has also been climbed by the north west slopes beginning from the upper reaches of the Edison River.

Access to Mt Dechen can also be gained from the Mahitahi Valley. Routes to the summit can be found by following the Edison River to either, the snowslopes overlooking the upper Edison, or to the saddle with the McCardell Glacier. Follow the snowslopes to the summit.