A reusable mailer bag includes a front panel, a rear panel, a pair of side panels, and a bottom panel. The panels together define a carrying volume including an opening opposite the bottom panel. A pair of handles are attached to an interior surface of the carrying volume and are configured for positioning entirely within the carrying volume during shipping. The pair of handles are configured to extend out of the opening to convert the reusable mailer bag for use as a carrying bag. A flap is attached to the rear panel at a first end and is configured to extend across the opening to close the opening. The flap is securable to the front panel at a second end by an adhesive strip. The flap is configured to be removed from the mailer bag after shipping.