The main campus is a rectangular area in downtown San Jose, California, bordered by San Fernando Street (north), Fourth Street (west), San Salvador Street (south), and Tenth Street (east).

The original Washington Square campus consisted of a rectangular, wooden building with a central grass quadrangle. The wooden buildings were destroyed by fire in 1880, and were replaced by a stone and masonry structure of roughly the same configuration in 1881. This building was declared unsafe following the 1906 San Francisco earthquake, and was in the process of being torn down when an aftershock of the magnitude that was predicted to destroy the building occurred and no damage was observed. The demolition was stopped, and the portions of the building still standing were made into four halls: Tower Hall, Morris Dailey Auditorium, Washington Square Hall, and Dwight Bentel Hall. These four buildings are the oldest on campus.

Formerly, San Carlos Street, Seventh Street and Ninth Street crossed the campus, creating essentially six small schools separated by roads clogged with traffic. Beginning in the fall of 1994, the streets were closed and converted to pedestrian walkways and green belts within the campus. San Carlos Street was renamed Paseo San Carlos, Seventh Street became El Paseo de César Chávez, and Ninth Street is now called the Ninth Street Plaza. As of 2004, all the dorms on the main campus are scheduled to be torn down and replaced with updated student housing. Three of the six brick blockhouses have been demolished, and the phase one of the new student village is scheduled to be completed in 2005. Following the completion of phase one, the remaining blockhouses and Joe West Hall will be demolished and replaced with phase two of the project.

The university boasts a year-round, outdoor Olympic-size swimming pool that is the largest in Northern California. The Event Center has basketball and racquetball courts, a small weight room, and a climbing wall. It also plays host to rock concerts and other events. The student union features a bowling alley and large game room.

Spartan Stadium, the other athletic fields, additional student housing and overflow parking are located on the South Campus on Seventh Street, about 1.5 miles south of the main campus.

San Jose State maintains a facility at Norman Y. Mineta San Jose International Airport as part of the Aviation Department, and manages the Moss Landing Marine Laboratories in Moss Landing, California, on the Monterey Bay, a cooperative research facility of seven CSU campuses.