An insulating shipping system may include six outer walls configured into a six-sided container; an insulating layer positioned within the outer walls and formed by a plurality of insulating members; and a thermal mass layer positioned within the insulating members and made from a plurality of thermal mass members. The thermal mass members may contain a thermal energy absorbing material. The container also may have a thermal buffer layer configured to fit within the thermal mass layer. All together, these layers form a passive, thermally stabile cargo cavity for transporting temperature-sensitive cargo.