San Marcos Post Office

Post office

420 N. Twin Oaks Valley Rd, San Marcos, CA 92069

(800) 801-9801

Call 1-800-801-9801 for appt.

Hours and addresses come from the State Department listing, updated November 2, 2026.

Book at USPS Directions Facilities in San Marcos Facilities in California

San Marcos Post Office accepts new U.S. passport applications in person in San Marcos, CA. First-time and child visits are booked on the USPS scheduler. Search ZIP 92069. How to apply · How to renew