Apparatus for sealing a puncture through tissue to a blood vessel includes a cartridge including a proximal end, a distal end sized for insertion into a puncture, and a lumen extending therebetween. A bioabsorbable plug is disposed within the lumen adjacent the distal end, and an anchoring element is disposed within the lumen proximal to the plug. A pusher member is disposed within the lumen for deploying the plug and anchoring element out the distal end of the cartridge. The plug may be formed from lyophilized hydrogel and the anchoring element may be formed from air-dried hydrogel, the anchoring element hydrating slower than the plug when exposed to an aqueous environment. During use, the plug and anchoring element are delivered into the puncture, the plug is cinched against the vessel wall. Protrusions on the anchoring element engage tissue surrounding the puncture to prevent proximal movement of the plug.