No, Costco does not offer a formal one-day guest pass or single-day shopping trial for non-members. To make purchases inside a Costco warehouse, individuals must either hold an active annual membership or be accompanied by a valid member. However, non-members can shop if they are using a Costco Shop Card (gift card) given to them by a member, or in certain regions where purchasing alcohol or visiting the pharmacy is legally mandated to remain open to the public without a membership.