A floating fastener includes a socket fastened to a first board member, a locking device axially slidably mounted in the socket and adapted for locking the socket and the first board member to a second board member, and an insulative barrel including a flexible barrel body attached onto the socket, a cap for capping on the barrel body to shield the locking device in the socket and to protect the socket and the locking device against corrosion and a flexible connecting strip connected between the barrel body and the cap.