A tunneling device is provided for implanting a natural tissue vascular graft in a body. The tunneling device may include a flexible sheath to assist in locating the vascular graft in the body. According to one example, a connector having a longitudinal coupler, such as a surgical tie, may be used to locate the natural tissue graft within the sheath. The natural tissue graft can be secured to the surgical tie when the sheath is retracted. Before tunneling, the sheath can be extended to cover the natural tissue graft to protect the natural tissue graft from damage and aid in locating the natural tissue graft in the body. When the natural tissue graft is positioned as desired in the body, the sheath is removed.