The only knife category Washington bans outright is the spring blade knife, a group that includes switchblades, gravity knives, and butterfly knives (balisongs). Every other knife is legal to own, but state law still controls how you conceal it, how you display it in public, and where you bring it, and several large cities add a blade-length limit that state statutes don’t mention. If you want a clear picture of what knives are illegal in Washington state, you have to read the possession ban, the carry rules, the location bans, and your city code together.
The Only Knife Washington Bans Outright
Under RCW 9.41.250, it is a crime to manufacture, sell, or even possess a spring blade knife. The statute defines one as any knife with a blade that opens automatically through a spring or other mechanical device, and it also covers any knife whose blade opens, falls, or ejects into position by gravity or by an outward or centrifugal thrust. That wording sweeps in gravity knives and butterfly knives along with classic switchblades, because all three rely on gravity or centrifugal motion to deploy.1Washington State Legislature. Washington Code 9.41.250 – Dangerous Weapons – Penalty
Assisted-opening knives are legal. The statute carves out knives with a built-in spring or detent that creates a “bias toward closure,” meaning the blade naturally wants to stay shut and you have to apply manual force to the blade itself to open it.1Washington State Legislature. Washington Code 9.41.250 – Dangerous Weapons – Penalty The practical test is where you push. If a button on the handle releases the blade, the knife is a prohibited spring blade knife. If you push against the blade itself with your thumb to overcome spring resistance, it is a legal assisted opener.
Who Can Legally Own a Spring Blade Knife
A few categories of people are exempt. Law enforcement officers, firefighters, and rescue personnel may carry spring blade knives on duty and may transport and store them off duty. Active-duty U.S. military members and the Washington National Guard are also exempt, as are manufacturers and distributors operating under government contracts.1Washington State Legislature. Washington Code 9.41.250 – Dangerous Weapons – Penalty If you don’t fit one of those categories, simple possession is a crime no matter where you are or why you have it.
Federal law also prohibits introducing a switchblade into interstate commerce, including shipping one across state lines, with penalties of up to $2,000, up to five years in federal prison, or both. The federal statute uses nearly identical “bias toward closure” language to exempt assisted-opening knives.2Office of the Law Revision Counsel. Manufacture, Transportation, or Distribution of Switchblade Knives
Concealed Carry of Other Knives
A knife that is perfectly legal to own can become illegal the moment you hide it. RCW 9.41.250 makes it a crime to “furtively carry with intent to conceal” any dagger, dirk, or other dangerous weapon.1Washington State Legislature. Washington Code 9.41.250 – Dangerous Weapons – Penalty Two things have to be true: the knife has to be concealed, and you have to intend to conceal it. A folding knife forgotten in a backpack pocket is not the same as a fixed blade tucked under a jacket, though in practice the difference often comes down to what an officer observes.
The phrase “other dangerous weapon” is broad. Courts have read it to cover essentially any instrument capable of inflicting serious harm when the circumstances suggest it is being carried as a weapon. Even a kitchen knife could qualify depending on the context. If a knife might raise questions, carry it openly.
Open Carry and Intimidation
Washington has no general ban on openly carrying a knife. You can wear a fixed blade in a belt sheath or clip a folder visibly to your pocket without violating state law. The limit is how you display it. RCW 9.41.270 makes it a crime to carry, exhibit, or draw any knife or other weapon in a way that shows an intent to intimidate someone or that would reasonably alarm people nearby.3Washington State Legislature. Washington Code 9.41.270 – Weapons Apparently Capable of Producing Bodily Harm – Unlawful Carrying or Handling – Penalty – Exceptions A hunting knife on your hip at a trailhead is unremarkable. The same knife brandished on a crowded sidewalk is not.
The statute doesn’t apply inside your own home or fixed place of business, to someone acting in lawful self-defense against an immediate threat, to law enforcement officers performing their duties, or to people in government-sponsored military activities.4Washington State Legislature. RCW 9.41.270 – Weapons Apparently Capable of Producing Bodily Harm – Unlawful Carrying or Handling – Penalty – Exceptions
Places Where Knives Aren’t Allowed
RCW 9.41.300 bans weapons in a defined list of locations. For most of those locations, “weapon” means any firearm, explosive, or instrument listed in RCW 9.41.250, which includes spring blade knives along with daggers, dirks, and other dangerous weapons.5Washington State Legislature. RCW 9.41.300 – Weapons Prohibited in Certain Places – Local Laws and Ordinances – Exceptions – Penalty A small folding pocket knife used as a tool rather than a weapon generally falls outside that definition, but the line is blurry and enforcement varies. The restricted places are:
- Public and private K-12 schools, school-provided transportation, and areas being used exclusively by schools.
- Restricted-access areas of jails, detention centers, and law enforcement buildings.
- Courtrooms, judges’ chambers, jury rooms, and adjacent corridors. For court areas, the definition of “weapon” is broader and explicitly includes any knife capable of causing death or bodily injury that is commonly used with that intent.6Washington State Legislature. Washington Code 9.41.300 – Weapons Prohibited in Certain Places – Local Laws and Ordinances – Exceptions – Penalty
- Any area of a bar or tavern classified by the state liquor and cannabis board as off-limits to people under 21.6Washington State Legislature. Washington Code 9.41.300 – Weapons Prohibited in Certain Places – Local Laws and Ordinances – Exceptions – Penalty
Law enforcement officers, active military members performing official duties, and on-duty security personnel are exempt from these location bans.5Washington State Legislature. RCW 9.41.300 – Weapons Prohibited in Certain Places – Local Laws and Ordinances – Exceptions – Penalty
Federal Buildings and Post Offices
Federal property runs on separate rules. Under 18 U.S.C. § 930, possessing a dangerous weapon in a federal facility is a federal crime, but the statute excludes a pocket knife with a blade shorter than 2½ inches, so a small folder generally passes in most federal buildings.7Office of the Law Revision Counsel. 18 USC 930 – Possession of Firearms and Dangerous Weapons in Federal Facilities Post offices are stricter: federal regulations prohibit carrying any dangerous or deadly weapon on postal property, openly or concealed, with no pocket-knife exception.8eCFR. Conduct on Postal Property Courthouses, military installations, and other specific sites can add their own restrictions on top.
City Rules That Override Common Assumptions
Washington does not preempt local knife laws, so cities and counties can add restrictions on top of state law. This is where people most often get caught off guard. Seattle, Tacoma, and Vancouver all define a “dangerous knife” as any knife with a blade longer than three and one-half inches and prohibit both open and concealed carry of such knives. State law has no comparable blade-length cap, so a knife that’s unquestionably legal to carry in rural Yakima County can get you cited in downtown Seattle.
Seattle’s ordinance also specifies that a dangerous knife carried openly in a sheath suspended from the waist is not treated as “concealed” for purposes of the city’s concealed-carry ban.9Court of Washington. Seattle Ordinance 110785 – SMC 12A.14.080 Before you carry anything with a blade longer than a few inches in a Washington city, check the municipal code.
Penalties
Most knife offenses in Washington are gross misdemeanors. That includes possessing a spring blade knife, furtively carrying a concealed dangerous weapon, and displaying a weapon in an intimidating manner.1Washington State Legislature. Washington Code 9.41.250 – Dangerous Weapons – Penalty3Washington State Legislature. Washington Code 9.41.270 – Weapons Apparently Capable of Producing Bodily Harm – Unlawful Carrying or Handling – Penalty – Exceptions A gross misdemeanor carries up to 364 days in county jail, a fine of up to $5,000, or both.10Washington State Legislature. RCW 9A.20.021 – Maximum Sentences for Crimes Committed July 1, 1984
The collateral consequences often matter more than the sentence. A conviction under RCW 9.41.270 for unlawful display triggers automatic revocation of any concealed pistol license you hold.11Court of Washington. Notice of Conviction Resulting in Revocation of Concealed Pistol License A weapons misdemeanor on your record can also complicate future background checks for employment, housing, and firearm purchases. Federal exposure is heavier: shipping a switchblade across state lines in violation of the Federal Switchblade Act can bring up to five years in federal prison.2Office of the Law Revision Counsel. Manufacture, Transportation, or Distribution of Switchblade Knives