[2] Service was extended along the East Line to Spring Street on May 12, 1989[2] serving Lemon Grove, and then to La Mesa and El Cajon on June 23, 1989.
[2] Service between El Cajon and Santee, which is not along the old SD&AE right-of-way, began on August 26, 1995.
[2] The "Bayside" extension of the Trolley in San Diego, which operates near the waterfront, opened on June 30, 1990.
[3] The first phase of the extension to Old Town, from C Street to Little Italy in downtown San Diego, opened on July 2, 1992.
[3] The "Mission Valley West" SDTI extension, which opened a new Trolley route between Old Town and Mission San Diego (which included the Qualcomm Stadium stop) commenced service on November 23, 1997,[3] just before San Diego's hosting of Super Bowl XXXII in early 1998.
[3] Stations along the Blue and Orange lines were renovated during 2010–15 as part of the Trolley Renewal Project.
The adjacent Santa Fe Depot/America Plaza/Courthouse stations, which are within walking distance of each other, also allow for transfer among the four lines.
About half of San Diego Trolley stations offer free park and ride lots.
[11][12] In September 2024, in part due to the signage on Trolleys and signage on the Green Line being updated to reflect the recently opened Copper Line, Alvarado station was renamed again to UC San Diego Health East.