Switchblades are illegal in California when the blade is two inches or longer, under Penal Code 21510. That statute makes it a misdemeanor to carry one on your person, keep it in a vehicle, or sell, loan, or give it away. Switchblades with blades shorter than two inches fall outside the ban, and simply owning a longer switchblade inside your home is not itself a crime. Where you run into trouble is the moment the knife leaves the house on you or in your car.
What Counts as a Switchblade in California
Penal Code 17235 defines a switchblade as a knife resembling a pocketknife with a blade two or more inches long that opens automatically by a button, pressure on the handle, a flick of the wrist, the weight of the blade, or “any other mechanism.”1California Legislative Information. California Code 17235 That catchall phrase is broad on purpose.
Butterfly knives (balisongs) are covered. They open when the handles swing apart with a flick of the wrist, which puts them inside the statutory definition. A butterfly knife with a two-inch or longer blade is treated the same as a spring-loaded automatic. Gravity knives, snap-blade knives, and spring-blade knives are also included.
Assisted-Opening Knives Are Not Switchblades
The definition specifically excludes a knife that opens with thumb pressure applied to the blade or a thumb stud, provided the knife has a built-in mechanism that resists opening or biases the blade back toward closed.2California Legislative Information. California Penal Code 17235 This is the “bias toward closure” test, and it draws the line between a legal assisted opener and an illegal automatic.
The practical version: if you have to apply deliberate thumb force to the blade or stud to start it moving, and the blade would spring back toward closed if you let go partway through, the knife is not a switchblade. If it deploys fully on its own once you press a button or flip the handle, it is. Federal law uses the same distinction, exempting bias-toward-closure knives from the Federal Switchblade Act.3Office of the Law Revision Counsel. 15 USC 1244 – Exceptions
The Two-Inch Threshold
Every prohibition in PC 21510 applies only to switchblades “having a blade two or more inches in length.”4California Legislative Information. California Penal Code 21510 A switchblade with a blade strictly shorter than two inches is not covered. You can carry one, keep it in your car, or sell it without violating this statute.
If your blade is near the line, treat it as over. Measurement disputes are exactly the kind of thing that turns a stop into a charge.
What Penal Code 21510 Prohibits
For a switchblade with a two-inch or longer blade, three acts are illegal:4California Legislative Information. California Penal Code 21510
- Possessing it in the driver’s or passenger’s area of any motor vehicle in a public place or a place open to the public. Glove box, center console, and door pocket all count.
- Carrying it on your person, in a pocket, bag, or on a belt, whether concealed or openly displayed.
- Selling, loaning, or giving it away. Money does not have to change hands. Retail sales, private transfers, and online orders shipped to California buyers are all covered.
The statute does not require intent to use the knife as a weapon. Prosecutors do not need to show you planned to hurt anyone. Having the knife on you or in your car is the offense.
Owning One at Home Is Legal
PC 21510’s vehicle restriction applies in “any public place or place open to the public,” and its carry prohibition covers having the knife “upon the person.” Neither reaches possession inside your own home. Keeping a switchblade in a drawer, displayed in a collection, or stored at your residence is not a crime under this statute. The legal risk begins when you step outside with it or put it in your vehicle.
California does not carve out an antique exemption. The age or collectible value of the knife does not change the analysis. An antique switchblade is legal to keep at home and illegal to carry or sell on the same terms as any other.
Places Where Stricter Rules Apply
State and Local Public Buildings
Penal Code 171b prohibits bringing any weapon described in Section 17235, which includes switchblades, into a state or local public building or any government meeting required to be open to the public.5California Legislative Information. California Penal Code 171b It also bans knives with locking blades longer than four inches, along with firearms and other weapons. A 171b violation is punishable by up to one year in county jail or state prison, so it is a more serious charge than a straight PC 21510 case.
Peace officers and active-duty military performing official duties are exempt, but that exemption does not extend to courtrooms, where even officers who are parties to a case cannot bring weapons.
Schools and College Campuses
Penal Code 626.10 prohibits knives with blades longer than two and a half inches on K-12 school grounds, and fixed-blade knives longer than two and a half inches on college and university campuses.6California Legislative Information. California Penal Code 626.10 A switchblade with a blade over two inches would already violate PC 21510 if you carried it, but 626.10 can add a separate charge when the knife is on school property.
Penalties for a PC 21510 Violation
Carrying, transporting in a vehicle, or transferring a switchblade with a two-inch or longer blade is a misdemeanor. The maximum penalty is six months in county jail, a fine of up to $1,000, or both.4California Legislative Information. California Penal Code 21510 First-time offenders without other charges often see probation or a diversion program rather than jail, but a conviction still creates a misdemeanor record.
Charges get more serious when a switchblade is tied to another offense. If you are arrested for assault or robbery and a switchblade is involved, the weapon can factor into charging decisions and sentencing on the underlying crime. A conviction can also affect employment screening and carry immigration consequences for non-citizens. If you are charged, two defenses worth raising with an attorney are misclassification of the knife (particularly when it sits near the assisted-opening line) and Fourth Amendment problems with the search that produced it.
Buying, Shipping, and Traveling
Federal law layers on top of California’s rules. The Federal Switchblade Act, 15 USC 1242, makes it a federal crime to introduce a switchblade into interstate commerce, transport it across state lines, or distribute it between states. The penalty is up to five years in prison and a $2,000 fine.7Office of the Law Revision Counsel. 15 USC 1242 – Manufacture, Transportation, or Distribution of Switchblade Knives Ordering a switchblade online from an out-of-state seller and having it shipped to California implicates both the federal ban and the California transfer prohibition.
The U.S. Postal Service will not mail switchblades to private individuals. Mailing is limited to federal and state government procurement officials ordering for official purposes and to authorized manufacturers or dealers shipping to those officials.8Postal Explorer. 442 Mailability
If you are flying, TSA prohibits all knives in carry-on bags. You can pack a knife in checked luggage if it is sheathed or securely wrapped.9Transportation Security Administration. Knives Getting a switchblade to California in checked baggage does not make it legal on the ground. The moment it goes in your pocket or your rental car, PC 21510 applies.
Federal buildings are their own category. Under 18 USC 930, bringing a dangerous weapon into a federal facility is punishable by up to one year in prison, and up to two years for a federal courthouse.10Office of the Law Revision Counsel. 18 USC 930 – Possession of Firearms and Dangerous Weapons in Federal Facilities The statute exempts pocket knives with blades under two and a half inches, so a switchblade at or above that length would not qualify.
Cities Can Add Their Own Restrictions
California has no statewide preemption law for knives, so cities and counties can pass ordinances stricter than PC 21510. Los Angeles, for example, prohibits openly carrying a dirk or dagger with a blade of three inches or longer, even though state law only bans concealed carry of those knives. Before carrying any knife in a specific city, check whether a local ordinance imposes further limits on blade length, carry method, or knife type.