Knife laws in Hawaii turn on the type of knife and how you carry it, not on blade length. Ordinary pocket knives and kitchen knives are legal to own and carry. Switchblades and gravity knives are banned outright. Butterfly knives, after a 2024 reform, are legal to own and carry openly but illegal to carry concealed. And any dirk, dagger, or similar deadly weapon carried concealed is a misdemeanor, whether or not you meant any harm by it.
What You Can and Can’t Carry
Three statutes in Chapter 134 of the Hawaii Revised Statutes do most of the work. HRS 134-51 covers dirks, daggers, and other deadly or dangerous weapons. HRS 134-52 bans switchblades. HRS 134-53 governs butterfly knives.1Justia. Hawaii Revised Statutes 134-51 – Deadly Weapons; Prohibitions; Penalty2Justia. Hawaii Revised Statutes 134-52 – Switchblade Knives; Prohibitions; Penalty Hawaii has no statewide blade-length rule and no preemption statute, so counties could theoretically add their own restrictions on top.
A common thread runs through all three: concealed carry is where the trouble starts. None of these laws require prosecutors to prove you intended to hurt anyone. Being found armed is enough.
Switchblades and Gravity Knives
HRS 134-52 makes it a misdemeanor to knowingly manufacture, sell, transfer, possess, or transport a switchblade knife anywhere in Hawaii. The statute defines a switchblade as any knife with a blade that opens automatically through hand pressure on a button or device in the handle, or through the operation of inertia, gravity, or both.2Justia. Hawaii Revised Statutes 134-52 – Switchblade Knives; Prohibitions; Penalty
That second clause is important. Gravity knives fall inside the switchblade definition. If your knife opens through gravity or centrifugal force, Hawaii treats it as a switchblade regardless of what it looks like or how the mechanism is marketed.
There is no collector exemption. Unlike states that allow switchblades to be kept at home or in a collection, Hawaii’s ban covers simple possession. Using or possessing a switchblade while committing a separate crime bumps the charge to a class C felony, and that felony sentence runs on top of whatever the underlying offense carries.
Butterfly Knives After the 2024 Change
Before 2024, HRS 134-53 banned butterfly knives outright. House Bill 2342, passed that year, rewrote the statute.3Hawaii State Legislature. Bills Passed by the Hawaii State Legislature Regular Session of 2024 Butterfly knives are now legal to own, buy, sell, transport, and carry openly. Only concealed carry remains prohibited.4Ninth Circuit Court of Appeals. Teter v. Lopez
The statute defines a butterfly knife as any knife with a blade encased in a split handle that unfolds manually through hand or wrist action, assisted by inertia, gravity, or both. Concealed carry is a misdemeanor. Carrying one hidden in a bag counts.
The statute includes a home defense: it is a valid defense to a concealed-carry charge that you were lawfully present in your own home when the alleged offense occurred. As with switchblades, using or possessing a butterfly knife while committing another crime is a class C felony stacked on top of the underlying charge.
Older summaries of Hawaii knife law still describe butterfly knives as flatly illegal. That is out of date.
Dirks, Daggers, and Concealed Carry
HRS 134-51 makes it a misdemeanor for anyone “not authorized by law” to carry concealed on their person or within a vehicle, or to be found armed with, a dirk, dagger, or other deadly or dangerous weapon.1Justia. Hawaii Revised Statutes 134-51 – Deadly Weapons; Prohibitions; Penalty Officers can arrest without a warrant. No intent to harm is required.
Hawaii courts have narrowed what counts as a “deadly or dangerous weapon” under this statute to instruments whose sole design and purpose is to inflict bodily injury or death. A 1975 Hawaii Supreme Court decision held that a diver’s knife is not a dangerous weapon or a dagger, and a 1976 ruling held the same for kitchen knives, cane knives, and butterfly knives. That is why an everyday pocket knife or kitchen knife is legal to own and carry, while a dagger or dirk concealed on your person is not.
Blade Length and Open Carry
There is no statewide blade-length limit in Hawaii. A long blade on a legal knife type does not by itself create liability, and a short blade on a switchblade does not save you. What matters is the category of knife and how you carry it.
Open carry of an ordinary knife is generally permissible. Context still matters. A visible knife that alarms people around you could support a disorderly conduct charge under HRS 711-1101 if an officer reads the situation as hazardous or alarming.5Justia. Hawaii Revised Statutes 711-1101 – Disorderly Conduct Since intent isn’t required for the underlying weapons charges either, the officer’s read of the scene tends to drive the outcome.
Where Knives Are Off-Limits
Schools
HRS 302A-1134.6 enforces a zero-tolerance policy for dangerous weapons on school grounds and at department-supervised activities, on or off campus. The statute specifically names dirks, daggers, butterfly knives, and switchblade knives. A student found with any of these can be excluded from school for up to 92 school days, and criminal charges under the weapons statutes can apply on top of that.6Justia. Hawaii Revised Statutes 302A-1134.6 – Zero Tolerance Policy
Federal Buildings
Under 18 U.S.C. 930, bringing a dangerous weapon into a federal building is a federal crime. There is a narrow carve-out: a pocket knife with a blade shorter than 2.5 inches is not treated as a dangerous weapon for purposes of the statute.7Office of the Law Revision Counsel. 18 U.S. Code 930 – Possession of Firearms and Dangerous Weapons in Federal Facilities Anything larger, or anything designed for combat, is prohibited. Federal courthouses screen more strictly and don’t recognize the pocket-knife exception.
Airports
The TSA bans knives of any kind in carry-on bags, with a narrow exception for rounded-blade or blunt-edged knives without serration, such as butter knives or plastic cutlery. All other knives go in checked luggage, sheathed or securely wrapped.8Transportation Security Administration. Sharp Objects TSA officers have final say at the checkpoint.
Penalties
Hawaii knife offenses fall into two tiers.
A misdemeanor conviction, which covers concealed carry of a deadly weapon under HRS 134-51, possession of a switchblade under HRS 134-52, and concealed carry of a butterfly knife under HRS 134-53, carries up to one year in jail and a fine of up to $2,000.
A class C felony conviction, which applies when a switchblade or butterfly knife is possessed or used in the course of another crime, carries up to five years of imprisonment. That felony sentence stacks on top of the penalty for the underlying offense.
Prosecutors can layer on related charges. Handling a knife in a threatening way that creates a substantial risk of serious injury can support reckless endangering in the first degree under HRS 707-713.9Justia. Hawaii Revised Statutes 707-713 – Reckless Endangering in the First Degree
A felony conviction also has federal consequences. Under 18 U.S.C. 922(g)(1), anyone convicted of a crime punishable by more than one year in prison loses the right to possess firearms.10ATF. Most Frequently Asked Firearms Questions and Answers A class C felony knife conviction clears that threshold. Restoring firearm rights after a federal disqualification typically requires a presidential pardon.
Confiscated knives are unlikely to come back. HRS 134-51 provides that any weapon covered by the statute is “summarily destroyed” by the chief of police or sheriff upon conviction. There is no process to reclaim a knife destroyed under that provision.
Bringing Knives Into Hawaii
Because most people arrive by air or sea, federal transportation rules apply on top of Hawaii’s own.
The Federal Switchblade Act prohibits introducing switchblade knives into interstate commerce or transporting them across state lines. The federal definition tracks Hawaii’s: a knife that opens automatically through hand pressure on a button, or through inertia or gravity.11Office of the Law Revision Counsel. 15 USC 1241 – Definitions Violations carry a fine of up to $2,000, up to five years in prison, or both.12Office of the Law Revision Counsel. 15 USC 1242 – Introduction, Manufacture for Introduction, Transportation or Distribution in Interstate Commerce; Penalty
The U.S. Postal Service restricts mailing switchblades to a narrow list of government supply and procurement officials. Private buyers and general commercial customers are excluded. Authorized manufacturers or dealers can ship to approved government recipients, but sending a switchblade through the mail to a regular customer is illegal.13Postal Explorer. 442 Mailability
U.S. Customs and Border Protection enforces the federal switchblade restriction at ports of entry. Switchblades and spring-loaded knives are subject to seizure when brought into the country. Folding knives with a blade bias toward closure are not treated as switchblades, and swords are not prohibited for import.14U.S. Customs and Border Protection. Traveling With a Personal Knife/Switchblade/Sword Into the United States
Who’s Exempt
HRS 134-51 applies only to people “not authorized by law,” which gives implicit cover to law enforcement officers and military personnel acting in an official capacity. HRS 134-11 spells out explicit exemptions for state and county law enforcement officers, members of the armed forces performing duties that require them to be armed, and certain federal and state employees whose work requires carrying weapons.15Justia. Hawaii Revised Statutes 134-11 – Exemptions By its terms, section 134-11 covers HRS 134-7 through 134-9 and 134-21 through 134-27, so its direct reach into the switchblade and butterfly knife statutes is limited.
Tradespeople, fishermen, hunters, and chefs routinely carry knives that could draw scrutiny under the dangerous-weapons statute. In practice, context provides the defense. A fillet knife in a tackle box or a chef’s knife in a kitchen bag reads as a work tool, not a concealed weapon. Carrying those same knives in a setting unrelated to your trade removes that practical shield, and Hawaii courts have consistently held that the circumstances of possession matter as much as the knife itself.