Mariachi Plaza station is an underground light rail station on the E Line of the Los Angeles Metro Rail system. It is located under 1st Street at the intersection of Boyle Avenue, with the main exit located at Mariachi Plaza, after which the station is named. The plaza is the historic gateway to the Boyle Heights neighborhood of Los Angeles. This station opened in 2009 as part of the Gold Line Eastside Extension and was one of two underground stations on the Eastside Extension.

The E Line is a 22-mile (35 km) light rail line in Los Angeles County, California. It is one of the six lines of the Los Angeles Metro Rail system, operated by the Los Angeles County Metropolitan Transportation Authority (Metro). The E Line runs east-west and serves 29 stations between East Los Angeles and Santa Monica. It interlines and shares five stations with the A Line in Downtown Los Angeles. Service operates for approximately 19 hours with headways of up to 8 minutes during peak hours. The E Line, the second-busiest light rail line in the system, saw an average of 41,902 passengers on weekdays in October 2023.