By train and bus is the standard approach from Geneva or Zurich. Take the train to Sierre (on the main Lausanne–Brig line), then the SMC funicular railway from Sierre up to Montana — the ride takes about 12 minutes and runs frequently. From Montana, a free ski bus connects the resort. Total journey from Geneva is around 2.5 hours; from Zurich closer to 3 hours.
By car, Crans-Montana is about 2.5 hours from Geneva via the A9 motorway to Sierre, then a winding road up the mountain. Parking in the resort can be expensive and limited in peak season. If you are skiing, most accommodation provides parking or is near a lift.
The nearest airports are Geneva (GVA), about 2.5 hours away, and Sion (SIO), a small regional airport just 30 kilometres down the valley in the Rhône Valley. Sion has limited seasonal connections but is extremely convenient if you can find a flight. Zürich (ZRH) is roughly 3 hours by car or train.