Self-tensioning occlusion devices and systems provide percutaneous access and closure of vascular puncture sites. One device includes a catheter body having a proximal end and a distal end, an occlusion member, and a tensioning member. The occlusion member, for example an expansible member, is disposed on a distal end of the body. The tensioning member, such as a spring or coil, is slidably disposed over the body and proximal to the expansion member. Generally, during application, the tensioning member will be positionable against subcutaneous tissue so as to lodge and anchor the expansible member against the puncture site. In particular, the expansible member allows for sealing of the puncture site while the tensioning member applies and maintains tension to the expansible occluder so that it is seated against the puncture site at a vascular surface.