The Pacific Surfliner is a designator for Amtrak passenger trains serving communities on the coastline of southern California between San Diego and Goleta. Several trains are available each day in both northbound and southbound directions, with bus service available between Los Angeles and Goleta during hours when that part of the track is in use by freight trains.

Due to the fact that neither San Diego nor Goleta is equipped with a roundhouse or a turntable, trains running on the Pacific Surfliner are arranged so that the last car is one equipped with engineer controls, so that the train can be operated in either direction, allowing for a quick turnaround.

Under the Atchison, Topeka, and Santa Fe Railroad, and later under Amtrak until the late 1990s, this same service was called the San Diegan.