text: are switchblades and butterfly knives illegal in california? if so, why? also, what would be considered conceiling a weapon? switchblades and butterfly knives are in fact illegal in california.  a pocketknife, however, is legal.  i know this for a fact because i always have two pocket knives with me at all times and since i interact with police officers on a daily basis, i already asked and was told it is legal as long as the blade is not open.  you don't even need a ccw permit to carry folding knives.  i live in san diego, so your city may have different ordinances.  the knives i carry are the sog trident and a kershaw ken onion series.