SC has no illegal length or type of knife you can carry but deals with use.You may find some sites that say different 2" or 3" but they are referencing the old law that was changed. (thank you Kniferights.org)
http://www.knifeup.com/south-carolina-knife-laws/
It is legal to own any type of knife in South Carolina.
Restrictions on Carry
It is legal to conceal carry dirk
It is legal to conceal carry a switchblade knife
It is legal to conceal carry a Balisong, or butterfly knife
It is legal to conceal carry a Bowie knife
It is legal to conceal carry a stiletto
South Carolina law explicitly excludes “dirks” and “knives” from the conceal carry statute, unless they are used with the intent to commit a crime or in the furtherance of a crime. The conceal carry statute however, does cover, “any other type of weapon, device, or object which may be used to inflict bodily injury or death”. Thus, while it may begin legal to carry a dirk or knife concealed, if the carrier were found carrying concealed under certain circumstances, it might become illegal.
What the Law States
§ 16-23-460. Carrying concealed weapons; forfeiture of weapons.
(A) A person carrying a deadly weapon usually used for the infliction of personal injury concealed about his person is guilty of a misdemeanor, must forfeit to the county, or, if convicted in a municipal court, to the municipality, the concealed weapon, and must be fined not less than two hundred dollars nor more than five hundred dollars or imprisoned not less than thirty days nor more than ninety days…..
…..(C) The provisions of this section also do not apply to rifles, shotguns, dirks, slingshots, metal knuckles, knives, or razors unless they are used with the intent to commit a crime or in furtherance of a crime.
Definition of Weapon
In 2008, the South Carolina legislature amended its definition of “weapon”, deleting “a knife with a blade over two inches long” from it. The definition now reads:
“weapon” means firearm (rifle, shotgun, pistol, or similar device that propels a projectile through the energy of an explosive), a blackjack, a metal pipe or pole, or any other type of device, or object which may be used to inflict bodily injury or death.
By deleting the phrase “knife with a blade over two inches long”, the legislature did not quite make it legal to carry a knife concealed, as the conceal carry statute specifically excludes knives as a weapon covered by it, unless the carrier uses the knife to commit a crime or in the furtherance of a crime.
Conclusion on South Carolina Knife Laws
It is legal to own or open carry any kind of knife in South Carolina. It is legal to conceal carry any type of knife, so long as you do not use the knife to commit or aid in the commission of a crime.
Sources
S.C. Code Ann. § 16-23-460 (2012)
S.C. Code Ann. § 16-23-405 (2012)