On a good day, the famous 'mirror lake' reflects extraordinary views of distant Aoraki/Mt Cook and Mt Tasman in its forest-shaded waters. The best time to visit is early morning or when the sun is low in the late afternoon, although the presence of an excellent cafe means that any time is a good time. It's extraordinary to think that this lake was carved out by the now distant Fox Glacier before it started its long retreat.
The shady, moss-lined 2.6km Lake Matheson Track circumnavigates the lake; allow 90 minutes walking at a slow pace. At the far end of the circuit you may, weather permitting, get the money shot, but failing that you can buy a postcard at the excellent gift store by the car park.
Branching off from the eastern side of the main track is the 8km-return Lake Gault Track, which gradually climbs 200m through virgin podocarp forest to another mirror lake. Allow three to five hours and expect to get wet and muddy feet.
