Castro Valley Post Office

20283 Santa Maria Ave, Castro Valley, CA 94546

Contact Numbers

Phone: 510-581-0159
Fax: 510-581-4074
TTY: 877-889-2457
Toll-Free: 1-800-Ask-USPS® (275-8777)

Retail Hours

Lobby Hours
PO Box Access Available

Monday 24 hours
Tuesday 24 hours
Wednesday 24 hours
Thursday 24 hours
Friday 24 hours
Saturday 24 hours
Sunday 24 hours

Last Collection Times

Monday 5:00pm
Tuesday 5:00pm
Wednesday 5:00pm
Thursday 5:00pm
Friday 5:00pm
Saturday 4:00pm
Sunday Closed

*This facility does not process US Passports applications or renewals. Check nearby locations below.

  • Burial Flags
  • Business Reply Mail Account Balance
  • Business Reply Mail New Permit
  • Duck Stamps
  • General Delivery
  • Money Orders (Domestic)
  • Money Orders (Inquiry)
  • Money Orders (International)
  • Pickup Accountable Mail
  • Pickup Hold Mail
  • PO Box Online
  • Sure Money
  • Lot Parking

Visit our Links Page for Holiday Schedule, Change of Address, Hold Mail/Stop Delivery, PO Box rentals and fees, and Available Jobs.

*Please call to verify information. Is anything incorrect? Let us know here

Nearby Post Offices:

822 C St
1.1 miles away

24438 Santa Clara St
1.8 miles away

San Lorenzo
15808 Hesperian Blvd
2.1 miles away

South San Leandro
14500 E 14th St
2.3 miles away


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I put an outgoing payment on my mailbox on 2/27 - not picked up and no mail received. I put the outgoing payment on my mailbox on 2/28 - not picked up and no mail received again!! I called 800 number online to see what was up - wait time 45 minutes. I called 510 number online - after approximately 10 rings it hung up!!! Some of us depend on the mail for bills and checks. What is going on???????????? I don't expect an answer.


Please tell delivery person not to leave packages too close to the street so that they are visible to a thief. Also, when raining, do not put packages at a location that can get wet.

* is not a part of, or affiliated with, the official United States Postal Service (USPS).