A vascular access port can include a base that can be attached to a vessel and a body extending away from the base in at least a vertical direction. A height of the body in the vertical direction can be sufficiently small such that the entire port can be implanted subcutaneously in a patient. The port can include a guidance passageway that is at least partially defined by the body and can direct an access device into a vessel of a patient when the port is attached to the vessel. In some arrangements, the guidance passageway includes a funnel region that decreases in size from a proximal end of the guidance passageway toward a distal end of the guidance passageway that defines an opening through the bottom surface of the port.
