The rune plateskirt is a plateskirt made out of runite. It requires level 40 Defence to wear.
It can be created with the Smithing skill by using 3 runite bars and a hammer on an anvil, this requires 99 Smithing and gives 225 Smithing experience.
Alternatively, it can also be purchased, along with its counterpart, rune platelegs, from Scavvo's Rune Store in the Champions' Guild south of Varrock or from Seddu's Adventurer's Store in Nardah, for 64,000 coins.
Along with the rune platelegs, this is the best bar-per-alch item in the game. If smithing for money, rune platelegs and plateskirt will give the best value for each bar.