Rapier

The Rapier is a very thin and elegant sword. Its equipment boni are very similar to those of a Rune Scimitar with only the stab and slash boni switched. It also has the same attack speed as a scimitar. The Rapier is the only rapier in the game of Oldschool Runescape.

Obtaining a Rapier
In order to get yourself a Rapier you need to do the quest Cabin Fever. Upon completion you will be given a Book o' piracy which in the players inventory is used to communicate with the pirates on Mos Le'Harmless.

Head to the docks in the south-west of the island and speak to Smith. You cannot purchase a Rapier through the trade option. Simply by talking to him and selecting the cutlasses option and then the rapier option you will be told a short story about how Smith found the Rapier. Then he will offer it to you for 25600 coins.