Generally not without a warrant — even when you are arrested.
In Riley v. California, the Supreme Court held that police must usually get a warrant before searching a cell phone.
The Riley Rule
In Riley v. California (2014), the U.S. Supreme Court recognized that modern phones hold the ‘privacies of life’ and held that police generally need a warrant to search a phone — even one seized during an arrest. Police can hold the phone while they seek a warrant; they cannot freely browse it.
Consent and Passcodes
Two things change the picture. If you consent, police can search — so do not consent. And you are generally not required to volunteer your passcode; whether police can compel a passcode or a fingerprint raises unsettled Fifth Amendment questions, so the safest course is to decline and ask for a lawyer.
If Your Phone Was Searched
If police searched your phone without a warrant and without valid consent, a motion to suppress (PC 1538.5) can seek to exclude what they found — texts, photos, location data. Given how much a phone contains, suppressing an unlawful phone search can take the heart out of a case.
Frequently Asked Questions
Can police search my phone without a warrant in California?
Generally no. Under Riley v. California (2014), police usually need a warrant to search a cell phone, even one seized during an arrest. They can hold the phone while they seek a warrant, but cannot freely browse it.
Do I have to give police my phone passcode?
You are generally not required to volunteer your passcode, and the safest course is to decline and ask for a lawyer. Whether police can compel a passcode or a fingerprint raises unsettled Fifth Amendment questions.
What if police searched my phone illegally?
A motion to suppress under PC 1538.5 can seek to exclude evidence from an unlawful phone search — texts, photos, location data. Because a phone holds so much, suppressing that evidence can gut the prosecution's case.
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Ahmed S. Hasan
San Francisco Criminal Defense Attorney · State Bar of California #364992
Ahmed S. Hasan is the founder of ASH Legal, a solo criminal defense practice based in San Francisco. The firm runs on flat-fee representation: one lawyer, one fee, from arraignment through resolution. No hourly billing. No surprise invoices.
Ahmed is a graduate of Emory University School of Law and a member in good standing of the State Bar of California (Bar #364992). His practice focuses on San Francisco misdemeanor defense — DUI, domestic violence, petty theft and shoplifting, drug possession, vandalism, trespassing, and assault and battery — with particular attention to diversion-track outcomes that end in dismissal under PC 1001.95, PC 1001.36 (Mental Health Diversion), PC 1001.80 (Military Diversion), and PC 1001.83 (Parental Caregiver Diversion).
Ahmed previously served as a post-bar clerk with the San Francisco Public Defender's Office, the city's largest indigent-defense practice. He is a member of the Asian Pacific American Bar Association of Silicon Valley.
He represents clients at the San Francisco Hall of Justice (850 Bryant Street) and the Civic Center Courthouse. The ASH Legal office is at 15 Boardman Place, Suite 301, San Francisco, CA 94103.
Free 30-minute consultations are available by phone or Zoom. (510) 545-6515 · ahmed@ashlegal.com