San Mateo is on the Caltrain commuter rail line between San Francisco and San Jose, with frequent service throughout the day. The station is at the north end of downtown, a short walk from Third and Fourth Avenues. From San Francisco, the journey takes around 35 minutes on the express or 45 on the local; from San Jose, about 40 minutes. Caltrain is the easiest way to get here without a car.
By car, San Mateo is directly on US-101 and El Camino Real, roughly equidistant between the two cities. Parking downtown is metered but generally available. The airport — San Francisco International (SFO) — is about 8 kilometres north, and a taxi or rideshare from the terminals to San Mateo takes around 15–20 minutes without traffic.