A proximally trimmable catheter is disclosed. In one embodiment, the catheter includes a multi-lumen catheter tube, one or more extension tubes, and a hub for fluidly connecting the two. In a first unlocked state, the hub is axially slidable along the catheter tube. The hub includes tube pins that are in fluid communication with the extension tubes. A cutting member is positioned to longitudinally cut the catheter tube during axial sliding of the hub along the catheter tube such that distal portions of the tube pins remain disposed within the lumens of the catheter tube. When positioned as desired, the hub is locked into a second locked state and is no longer axially slidable along the catheter tube. The tube pins are fluidly sealed within the lumens of the catheter tube as to establish fluid communication between the extension tubes and the lumens via the tube pins.