A system for preparing the sacroiliac (SI) joint for an SI joint fusion, and optionally delivering an implant to the SI joint, is described herein. The implant is inserted via an inferior inlet approach. A sliding joint finder is inserted into the joint, followed by insertion of a working cannula. The working cannula is operatively coupled to the sliding joint finder, in that it is configured to fit over the sliding joint finder, allowing subsequent removal of the sliding joint finder, and providing a hollow cavity for joint fusion preparation, decortication and insertion of an implant. This system and method provides a less invasive and safer approach for fixing an SI joint or delivering an implant to the SI joint than currently available methods.