Nationally, Saint Arnaud falls under the West Coast-Tasman electorate, which is currently held by Damien O'Connor of the Labour Party.

Mostly catering for a small number of locals and tramping and skiing tourists, the centre of Saint Arnaud has a village store with postal services, a petrol station, a cafe-restaurant, camping facilities, motels, chalets and specialist accommodation for trampers at the Travers-Sabine Lodge youth hostel.

A water taxi service operates from a jetty at the northern end of Lake Rotoiti, near to a DOC campsite at Kerr Bay.

A daily shuttle bus service along State Highway 63 provides connections to Nelson, Murchison, Greymouth, Blenheim, Westport and Picton.

The western part of the township includes a local Department of Conservation (DOC) Visitor Centre, with interactive displays and comprehensive information about the wildlife and environmental management of the Nelson Lakes National Park.

From here walkers can complete the circuit back to Saint Arnaud by either crossing a low saddle to the valley of Lake Rotoiti, via the Speargrass Track, or by ascending a higher route via Mount Angelus.

In winter, snow sports take place primarily at Rainbow Skifield on the eastern side of the Saint Arnaud Range.

Other local recreational activities include fishing, hunting, kayaking, small boat sailing, and gliding.

Korere Tophouse Road leaves SH 63 four kilometres east of Saint Arnaud, and provides the most direct route to Richmond and Nelson.

Electricity is fed from Transpower's national grid at its Kikiwa substation, 15 km (9 mi) north of the town.