State Route 75 (SR 75) is a short, 13-mile (21 km) expressway in the U.S. state of California. It is a loop route of Interstate 5 (I-5) that begins near Imperial Beach. The route continues north along the Silver Strand, a thin strip of land. SR 75 passes through the city of Coronado as Orange Avenue and continues onto the San Diego–Coronado Bay Bridge, a bridge that traverses the San Diego Bay, before joining back with I-5 near downtown San Diego.

SR 75 begins as Palm Avenue at I-5, heading westbound from the Southland Plaza mall. The route travels west between the communities of Palm City and Nestor before entering the city limits of Imperial Beach. In Imperial Beach, SR 75 curves to the north, becoming Silver Strand Boulevard and crossing into Coronado and continuing onto the peninsula containing Coronado Island, separated from the mainland by San Diego Bay. The highway continues through the Silver Strand Training Complex and the South Bay Study Area before entering the Coronado Cays subdivision and paralleling Silver Strand State Beach.

After this, SR 75 passes through the United States Naval Amphibious Base for a few miles before entering downtown Coronado. The highway becomes Orange Avenue and turns north-northeast as the main street through Coronado. SR 75 intersects SR 282 at the one-way couplet of Third and Fourth Streets; SR 282 continues west on Third Street and returns to SR 75 on Fourth Street, while SR 75 continues east on Fourth Street and heads west towards Orange Avenue on Third Street. The one-way couplet is brief, and SR 75 briefly becomes a divided highway before crossing the Coronado Bridge. While on the bridge, SR 75 crosses into the city of San Diego again.

Once on the mainland, SR 75 has a northbound exit to National Avenue and a southbound entrance from Cesar E Chavez Parkway. Through traffic is directed onto I-5 south or north in Logan Heights, and SR 75 ends.

This route is eligible for the State Scenic Highway System. It is signed as a scenic route for nearly its entire length, from the Imperial Beach city limit to Avenida del Sol in Coronado, meaning that it is a substantial section of highway passing through a "memorable landscape" with no "visual intrusions", where the potential designation has gained popular favor with the community. SR 75 is part of the National Highway System, a network of roadways important to the country's economy, defense, and mobility.

The route was originally established in 1963 with two segments: from I-5 to the ferry across San Diego Bay from Coronado to downtown, and from SR 125 to I-5. In 1967, the Coronado Bridge was scheduled to be added to the route once it was completed, and the portion from Fourth Street to the ferry was deemed as temporary until the bridge opened. However, before the bridge opened, in 1968, the changes took effect; the bridge opened on August 3, 1969. In 1976, the southern section from I-5 to SR 125 was renumbered SR 117, which later became SR 905.

On June 8, 2010, Coronado voters decided against Proposition H, which would have advised the city to undergo further investigation into building a tunnel between the Coronado bridge and the San Diego Naval Base. This concluded ten years of studies and proposals by the city of Coronado to find a way to reduce traffic to the naval station during rush hour. Critics of the proposal did not believe that the tunnel would resolve the traffic issues on the northern part of SR 75 or on SR 282. Following this, the Coronado City Council voted to abolish the Tunnel Commission.

Except where prefixed with a letter, postmiles were measured on the road as it was in 1964, and do not necessarily reflect current mileage. The entire route is in San Diego County.