Oceanside Transit Center is a major railway interchange in Oceanside, California, serving both intercity and suburban/commuter services. The station is used by Amtrak on the route of its Pacific Surfliner service between San Diego and San Luis Obispo. It is also a terminus for two different regional transit operators – Metrolink, the commuter rail operator for the Los Angeles area, has two of its services, the Orange County Line and Inland Empire–Orange County Line, that terminate at Oceanside, while the North County Transit District, the operator for most of the public transport in the North County, has its COASTER and SPRINTER services also terminating at Oceanside. Oceanside Transit Center is also served by Greyhound Lines, numerous BREEZE buses, and is also the terminal for Riverside Transit Agency's Bus Route 202 to Temecula and Murrieta. COASTER and Metrolink trains going out of service will head to Stuart Mesa but due to the small facility, some Metrolink sets will either be kept at the nearby Fallbrook Yard or stored on an empty track south of the station.

Oceanside is a city on the South Coast of California, located in San Diego County. The city had a population of 174,068 at the 2020 United States census, up from 167,086 at the 2010 census, making it the most populous city in the North County region of San Diego. The city is a popular tourist destination, owing to its historic landmarks, beaches, and architecture.