Is It Legal to Put a GPS Tracker on Someone’s Car in California?

A suspicious spouse buys a $30 tracker online. Maybe it’s a worried parent who wants to know where their teenager really goes after school. Or it’s a business owner trying to prove an employee isn’t using a company truck for side jobs. The device ships in two days and takes five minutes to attach.

Is it legal to track someone’s car in California, though? The honest answer is usually not. Getting it wrong can turn the person doing the tracking into the one facing criminal charges instead of the one holding the answers.

This surprises people constantly. GPS trackers are cheap, small, and easy to buy from any major retailer. None of that makes using one on someone else’s car legal by default. The gap between “easy to buy” and “legal to use” catches far more people off guard than it should, including plenty of people who genuinely believed they had a good reason.

California’s GPS Tracking Law, in Plain English

California has an actual statute covering this exact situation. It says no person or entity can use an electronic tracking device to determine someone’s location or movement without consent. That rule is written directly into Penal Code section 637.7.

There are only two real exceptions. The registered owner, lessor, or lessee of a vehicle can consent to tracking on that specific vehicle. Law enforcement can use tracking devices lawfully, typically backed by a warrant. Outside those two situations, tracking someone’s location without their permission is against the law, full stop.

This applies to spouses. It applies to employees. It applies to adult children, roommates, and business partners equally. The law doesn’t carve out an exception for suspicion, jealousy, or even a genuinely good reason to worry about someone’s safety, no matter how well-intentioned the person doing the tracking might be.

The reasoning behind the law is simple enough. California treats a person’s location as genuinely private information, worth protecting even from people close to them. The short version: is it legal to track someone’s car in California without telling them? Almost never, unless the vehicle itself belongs to the person doing the asking.

The Ownership Loophole (And Why It’s Narrower Than People Think)

Here’s where people get tripped up. The exception belongs to the registered owner of the vehicle, not to anyone with a good reason to want answers.

If a car is titled solely in one spouse’s name, the other spouse generally can’t legally place a tracker on it. That’s true even during an otherwise intact marriage, and it’s often the exact scenario that turns a private suspicion into a criminal complaint. Joint ownership changes the picture, since either registered owner can typically consent on a jointly titled vehicle. A parent tracking a car registered in their own name usually falls within the exception. That’s true even if their teenager is the one actually driving it day to day. A parent tracking a car titled solely in the teenager’s own name is a different, riskier situation entirely.

Phone-based tracking apps complicate things further. Section 637.7 was written around physical devices attached to vehicles. Courts have had to work out separately how it applies to modern tracking apps and shared location features. Family-safety software adds another wrinkle, since it often blurs the line between real consent and quiet monitoring long after that consent was actually given. That gray area doesn’t make phone tracking automatically safe. It just makes it a more complicated legal question than most people assume walking in.

What Happens If You Track Someone Without Consent

Violating this law isn’t a slap on the wrist. It’s a real criminal offense with real consequences attached, not just an awkward conversation if discovered.

Unauthorized tracking under Penal Code 637.7 is charged as a misdemeanor. That can mean up to six months in county jail, along with a fine on top of it. The person being tracked can also pursue civil damages separately from any criminal case, on top of whatever the criminal court imposes. For anyone holding a professional license tied to surveillance or security work, there’s more at stake still. A conviction can put that license itself at risk, on top of any jail time or fines already on the table.

None of this requires proof that anything was actually done with the tracking data once collected. Simply placing the device without consent is enough to violate the statute entirely on its own. These devices also tend to surface at inconvenient moments. A routine oil change, a car wash, or a mechanic’s inspection is often exactly how these situations come to light.

When Surveillance Crosses Into Stalking

There’s a flip side worth understanding too. Unauthorized tracking isn’t just illegal on its own. It’s also exactly the kind of behavior that can support a restraining order against the person doing it, especially when it’s part of a broader pattern rather than an isolated incident.

Someone who discovers an unexplained device on their car has grounds worth taking seriously. That’s especially true if it’s paired with a pattern of being followed or monitored elsewhere. California courts offer a specific process for civil harassment and stalking-related restraining orders. Unauthorized electronic tracking fits squarely within the kind of conduct those orders are designed to address. A counter-surveillance sweep, checking a vehicle or home for hidden tracking devices, is often the first concrete step. It’s frequently what turns a vague suspicion into documented, actionable evidence a court or an officer can actually act on.

How Licensed Investigators Do This Differently (and Legally)

This is exactly why professional surveillance doesn’t lean on GPS trackers purchased online and slapped under a bumper.

Licensed investigators build cases around methods that actually hold up. That means physical surveillance from public locations, photo and video documentation, and records obtained lawfully from the start. A report built on evidence gathered illegally isn’t just risky for whoever ordered it. It’s often worthless in court, since a judge can exclude evidence tied to an unlawful tracking violation entirely, regardless of what it shows. That single mistake can undo months of otherwise solid work on a case.

The safer, more effective path is working with someone who already knows exactly where that legal line sits. That beats finding out the hard way, after a device gets discovered or an entire case falls apart because of how the evidence was collected. Consultations up front, before any surveillance begins, exist specifically to catch these problems while they’re still cheap and easy to avoid.

Get Surveillance Done the Legal Way

Excell Investigation has conducted undercover surveillance across Los Angeles County for decades. The cases span infidelity suspicions, child custody disputes, workers’ compensation fraud, and corporate loss prevention. Every investigator is licensed by the state, and every method stays within California law, so the resulting evidence actually holds up when it matters most, in court or otherwise.

Before buying a tracker online and hoping for the best, talk to a licensed investigator first. They already know what’s legal and what isn’t, and they usually get better answers faster too. Request a surveillance consultation for a free quote, or call 800-644-6080 today. Getting the answer legally is worth far more than getting it fast, and far cheaper than the alternative down the road.