An implanter for inserting subcutaneous implants includes a handle for grasping the implanter during implantation, a hollow cannula receiving the implant, and a rod for releasing the implant from the cannula. The rod is longitudinally fixed within the handle while the cannula slides over the rod to release the implant. The cannula is moved over the rod by a sliding actuator mounted in a track of the handle. The actuator is locked in an extended position to prevent unintended release of the implant. Preferably, the implanter is a single-use device having an actuator locking feature preventing reuse.