By road is the standard way in. From Sacramento or the Bay Area, take Interstate 80 over Donner Pass to Truckee, then Highway 89 south for 14 miles to Tahoe City. The drive is about 3 hours from San Francisco in good conditions, but Donner Pass closes regularly in winter storms — carry chains November to April and check Caltrans road conditions before setting off.
By air, Reno-Tahoe International (RNO) is the closest airport at about 55 miles east, around 75 minutes by car in good weather. Sacramento (SMF) is a longer drive (just over 2 hours) but often cheaper. Several shuttle companies serve both airports.
By bus, Greyhound serves Truckee from Sacramento and Reno; TART (Tahoe Area Regional Transit) connects Truckee with Tahoe City and the rest of the north shore.