Abstract: Introducers and dilators that include expansion features configured to dilate expandable access sheaths, and expandable access sheaths, are described herein. The introducer can include an expansion feature disposed on an elongate shaft. The expansion feature can include a larger outer diameter than the distal end of the elongate shaft or another portion of the elongate shaft. The expansion feature can be configured to dilate a portion of an expandable access sheath when the elongate shaft is translated within the expandable access sheath. Expandable access sheaths can comprise expandable distal end portions configured to be maintained in a closed state by, for example, a tensioned cord portion disposed around a circumferential portion of the expandable distal end portion, a plurality of pleats comprising material configured to attract one another, a circumferential portion with a weakened joint, and/or a weakened portion on a sidewall of the expandable distal end portion.