California note
San Diego transit usually comes down to MTS and PRONTO
San Diego transit has a simple core once you know the names. MTS is the main bus and Trolley system for many city trips. PRONTO is the fare card and app layer used on MTS buses and Trolleys.
San Diego trips can mean beach days, downtown events, border-area travel, college stops, and long east-west rides. A Trolley line may do the clean rail part. A bus may handle the neighborhood part. PRONTO ties the fare side together, but it still needs to be tapped or scanned the right way for the trip.
Check the MTS route and fare pages by the exact ride. The PRONTO page explains the card, app, validators, two-hour ride window for many one-way fares, and fare capping. If a trip reaches outside the MTS area, check the other agency too instead of assuming the same rule follows you.
Where to see it
MTS bus and Trolley routes, Trolley station validators, and the PRONTO app or card.
Official sources
Official pages
Reviewed July 6, 2026
Current rules, forms, fees, deadlines, maps, and office instructions.
Rules, forms, fees, deadlines, and office procedures can change. Check the current page before you file, pay, or rely on a date.
Connected places
Open the local directory
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