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San Diego California Knife Laws

The California Penal Code includes knife laws which govern what kind of knife a man or woman can carry in public, how he can carry it, and where he can carry it.


The most common questions I am asked are "Is a combat knife legal?" or "Can I own a karambit?" or "How big a knife can I carry?" Feel free to contact attorney Rodger Pasieczny with any questions at (619) 512-3412, call or text.

The law doesn't care about the name of a knife. A policeman or prosecutor will look at its characteristics. Is if folding? Is it fixed blade? Does it have a sharp tip? Here is some guidance:

  • A fixed blade with a sharp tip counts as a "dirk or dagger." Legal to own. Concealed carry violates the law. Open carry does not.
  • A closed folding knife can be carried in a pocket. Legal to own.
This tells you that most knives are legal to own but may not be legal to carry in public in a pocket, purse or backpack. 

There is no length limit for knives in California, except where there is. In most public places there is no limit. Some cities have their own laws on blade lengths. San Diego does not. There are size limits for schools, government buildings and airports.

Legal and Illegal Knives - The What

Folding Knives

Generally, a folding knife that is carried with the blade closed does not violate California law. This includes knives with thumbstuds, thumb holes or “wave” openers. Folding knives that lock open are not prohibited. Knives with spring-assist features are legal if the knives are biased to the closed position and need to overcome a force before opening. There is no blade length restriction, except on school property, in airports, and state and federal buildings. 

A folding knife carried with the blade open is classified as a “dirk or dagger.” 

The Fixed Blade - “Dirk or Dagger”

Owning a dirk or dagger does not violate the law. Most fixed blade knives are classified as dirks or daggers. 

“Dirk” or “dagger” share a definition under California law. Penal Code section 16470 defines dirk or dagger as:

  • a knife or other instrument 
  • with or without a handguard 
  • that is capable of ready use as a stabbing weapon 
  • that may inflict great bodily injury or death. 

This definition has been found to include kitchen knives, swords, hunting knives and scissors. It includes most anything that can be used as a stabbing weapon. Dirks and daggers are not prohibited weapons but they can not be carried in a concealed manner. There is no blade length restriction, except on school property, in airports, and state and federal buildings. 

Prohibited Knives


The category of switchblades includes pocket knives with spring-blades, snap-blades or gravity knives. There is an exception for legal switchblades when the blade is less than two inches long. Penal Code section 17235 defines switchblades as having 

  • a blade (that) 
  • can be released automatically by a flick of a button or
  • pressure on the handle or 
  • flip of the wrist or 
  • other mechanical device, 
  • or is released by the weight of the blade 
  • or by any type of mechanism whatsoever. 

It does not include a knife that opens with one hand utilizing thumb pressure applied solely to the blade of the knife or a thumb stud attached to the blade, provided that the knife has a detent or other mechanism that provides resistance that must be overcome in opening the blade, or that biases the blade back toward its closed position.

A switchblade may not be possessed in a public place or carried in a car. It can not be carried on a person. It cannot be sold or transferred in California. To do any of these is a misdemeanor by Penal Code section 21510.

A “butterfly knife” is considered a switchblade, including the two inch blade exception. There is no longer a separate section of the law regarding butterfly knives.

Other Prohibited Knives

The complete list of knives prohibited by California law is long and frankly, strange. It includes:

  • air gauge knife, as prohibited by Section 20310.
  • ballistic knife, as prohibited by Section 21110.
  • belt buckle knife, as prohibited by Section 20410.
  • cane sword, as prohibited by Section 20510.
  • lipstick case knife, as prohibited by Section 20610.
  • shobi-zue, as prohibited by Section 20710.
  • shuriken, as prohibited by Section 22410.
  • writing pen knife, as prohibited by Section 20910.
  • a punch dagger is a "dirk or dagger" but may also be brass knuckles, prohibited by Section 21810.

Carrying a Knife - The How

Concealed and Open Carry

Penal Code section 21310 makes it a misdemeanor to: 

  • carry concealed upon the person 
  • any dirk or dagger

Additionally the person must know 

  • that he was carrying it and
  • it could readily be used as a stabbing weapon.

A pocketknife or folding knife is not a dirk or dagger unless the blade of the knife is exposed and locked into position. A pocketknife may be concealed if closed. 

A recent case, People v. Castillolopez, ruled that an open Swiss Army knife is not a fixed knife and cannot be illegally concealed. The knife lacked a locking blade and could not be "fixed open." The "opened or exposed blade of the concealed folding Swiss Army knife Castillolopez was carrying at the time of his arrest was [not] firmly fixed in place or securely attached so as to be immovable, such that it was locked into position within the meaning of section 16470. Thus, we also conclude there is no substantial evidence to support the jury's verdict that Castillolopez carried a concealed dirk or dagger in violation of section 21310. 225 Cal. App. 4th 638 - Cal: Court of Appeal, 4th Appellate Dist., 1st Div. 2014, affirmed California Supreme Court S218861.

While concealed carry of a dirk or dagger is illegal, open carry is allowed. The California “open carry” law is codified in Penal Code section 20200:

  • A knife carried 
  • in a sheath 
  • that is worn openly 
  • suspended from the waist of the wearer 
  • is not concealed.

The open carry law provides guidelines for legal carry of fixed-blade knives in California. It is likely that other forms of open carry are legal too because the State could not prove the “concealed upon the person” element of section 21310. For instance, a scuba diver with a dive knife strapped to their leg, worn over the wetsuit. 

The best practice for California knife owners who carry fixed blade knives is to strictly comply with Penal Code section 20200. Wear your knife in a sheath, on your belt and do not cover any part of it under a shirt or jacket.

Knives in Public - The Where

The previous sections describe the state of the knife laws of California and the legal ways to carry knives in public. However, that is not the end of the analysis. There are places which receive special consideration and have more stringent restrictions on knives. 

When looking at the places with more restrictive knife laws, it is important to remember that the concealed “dirk or dagger” law of Penal Code section 21310 still applies. For instance, a 2 1/2 or 4 inch blade length limitation creates a new restriction. A short blade still may be a dirk or dagger that should be worn in accordance with the “open carry” law.


All K-12 schools in California have heightened restriction on knife possession. For any public or private school that is a kindergarten, grade school or high school it is a misdemeanor or felony to bring or possess any

  • dirk
  • dagger
  • ice pick
  • box cutter
  • razor blade
  • razor with an unguarded blade
  • knife with a blade longer than 2 1/2 inches, or
  • folding knife with a blade that locks into place.

Penal Code sections 626.10(a) creates these new limits. There is no “concealment” element to the school knife law and no “open carry” exemption. Anything that could be a “dirk or dagger” is prohibited.

Two new prohibitions deserve comment. Section 626.10 includes the first limits of blade lengths and locking knives. First, all folding knives with locking mechanisms are prohibited, no matter the size. Second, all knives with blades over 2 1/2 inches are prohibited. The Court of Appeals interprets the word “blade” as only the sharpened edge of the knife. (In re Rosalio 35 Cal.App.4th 775 41 Cal.Rptr.2d 534 (1995) “In determining wether a knife has ‘a blade longer than 2 1/2 inches,’ within the meaning of section 626.10, subdivision (a), only the sharpened portion should be measured.”)

The only exemptions to section 626.10 are for law enforcement members, people with permission of the school, and employees who need knives for food prep or in the scope of their employment. 

Colleges and Universities have a different set of prohibitions. Generally, the institutes of higher learning are less restrictive. At any public or private university or California Community College it is a misdemeanor or felony to bring or possess a:

  • dirk
  • dagger
  • ice pick or 
  • fixed blade knife with a blade longer than 2 1/2 inches.

Penal Code section 262.10(b). There is no prohibition on folding knives or locking folding knives. The blade length limit only applies to fixed blades.

None of this should be understood that schools cannot have rules in place that ban students from carrying any knifes at school. What is prohibited by school rules and what is criminal are two different matters. 

San Diego Public Spaces and Parks

The San Diego Municipal Code prohibits throwing of sharp pointed missile or darts, including throwing knives. The prohibition covers public streets, sidewalks and public gathering places in the city of San Diego. The code section is 53.15.

The San Diego County Code of Regulatory Ordinances prohibits possession of a "throwing knife" in County parks. The section is 41.117(a)

 State Government Buildings, Airports and Harbor Ports

Continuing with “Where” knife laws are more restrictive: government buildings, ports, harbors and airports have additional laws limiting the kind of knives that can be carried.

Penal Code section 171b criminalizes carrying a knife in any state or local public building or at any meeting required to be open to the public:

  • switchblades (blade greater than two inches)
  • cane swords, belt buckle knives, shrunken, etc.
  • Any knife with a blade length in excess of four inches, 
    • the blade of which is fixed or is capable of being fixed in an unguarded position 
    • by the use of one or two hands.

The offense is a misdemeanor or felony. 

Penal Code section 171c(2) prohibits possessing a knife within the State Capitol, any legislative office, any hearing room in which any committee of the Senate or Assembly is conducting a hearing, the Legislative Office Building at 1020 N Street in the City of Sacramento, or upon

the grounds of the State Capitol, that is: 

  • a switchblade (blade greater than two inches)
  • cane swords, belt buckle knives, shrunken, etc.
  • Any knife with a blade length in excess of four inches, 
    • the blade of which is fixed or is capable of being fixed in an unguarded position 
    • by the use of one or two hands,
  • if notice of the law is posted.

Seaports and airports have similar prohibitions. It is important to note that Federal Law governs air travel and TSA agents will not allow any knife through security screening areas. There is no exemption for small knives, folding knives or multitools. Knives may not be carried on the person or in carry-on luggage. They may travel in checked luggage however. TSA agents will allow a person the return to the airline desk and check a knife (in personal experience.) Otherwise they will confiscate the knife. 

A list of TSA prohibited items is found at

California Penal Code section 171.5 criminalizes knowing possession of a box cutter, straight razor, or knife with blade greater than four inches in an airport’s or port’s “sterile area.” The “sterile area” is a portion of an airport defined in the airport security program to which access generally is controlled through the screening of persons and property. 

If TSA would allow you to get a knife on an airplane 49 U.S. Code section 46505 makes it a felony to carry a concealed dangerous weapon on air transportation.

Federal Buildings

Federal buildings prohibit the knowing possession of “dangerous weapons.” A “dangerous weapon” is anything readily capable of causing death or serious bodily injury. The law under 18 U.S. Code section 930 creates an exemption for pocket knives. A legal pocket knife must have a blade under 2 1/2 inches in length. 

It is a misdemeanor to cary a dangerous weapon in a Federal facility. It is a felony to carry a dangerous weapon in a Federal Court. There is an exemption for lawful hunters, Federal and State law enforcement, and military members. 

Federal Switchblade Law

Federal law prohibits possession of switchblades on Federal territories including all land within the limits of any Indian reservation under the jurisdiction of the United States Government. 15 U.S. Code section 1243. 

15 U.S. Code section 1242 prohibits “interstate commerce” of switchblade knives. The term “interstate commerce” means commerce between any State, Territory, possession of the United States, or the District of Columbia, and any place outside thereof.