An expandable shipping package for shipping one or more articles preferably consisting of or consisting essentially of one or more flexible materials, the package having a top panel, a bottom panel opposed to the top panel, a first end panel extending between the top panel and the bottom panel, a second end panel opposed to the first end panel and extending between the top panel and the bottom panel, a first side panel extending between the top panel, the bottom panel, the first end panel and the second end panel, a second side panel opposed to the first side panel and extending between the top panel, the bottom panel, the first end panel and the second end panel, a central plane bisecting the first end panel, the second end panel, the first side panel and the second side panel, the package comprising: a. a flexible inner sheet having an inner sheet first portion, an inner sheet second portion, an inner sheet first surface, an inner sheet second surface; b. a flexible outer sheet having an outer sheet first portion, an outer sheet second portion, an inner surface and an outer surface, at least a portion of the outer surface of the outer sheet first portion being joined to the first surface of the inner sheet first portion to form one or more first primary expansion chambers therebetween, and at least a part of the inner surface of the outer sheet second portion being joined to the first surface of the inner sheet second portion to form one or more second primary expansion chambers therebetween; at least a portion of the second surface of the inner sheet first portion disposed in face-to-face relationship with and joined to a portion of the second surface of the second portion of the inner sheet forming an article reservoir therebetween, the article reservoir having a periphery where the inner sheet first portion and the inner sheet second portion are joined together and a central area within the periphery; c. an expansion port in fluid connection with at least one of the first primary or second primary expansion chambers (241, 242) through which the expansion material can be introduced into the expansion chamber (241, 242); and d. a closeable opening into which the one or more articles may be inserted, the opening extending from an exterior of the package to the article reservoir; wherein the package when expanded has a generally parallelepiped shape, characterized in that the expandable shipping package further comprises: e. a flexible secondary outer sheet at least partially joined to the outer sheet outer surface to form a plurality of secondary expansion chambers. a. a flexible inner sheet having an inner sheet first portion, an inner sheet second portion, an inner sheet first surface, an inner sheet second surface; b. a flexible outer sheet having an outer sheet first portion, an outer sheet second portion, an inner surface and an outer surface, at least a portion of the outer surface of the outer sheet first portion being joined to the first surface of the inner sheet first portion to form one or more first primary expansion chambers therebetween, and at least a part of the inner surface of the outer sheet second portion being joined to the first surface of the inner sheet second portion to form one or more second primary expansion chambers therebetween; at least a portion of the second surface of the inner sheet first portion disposed in face-to-face relationship with and joined to a portion of the second surface of the second portion of the inner sheet forming an article reservoir therebetween, the article reservoir having a periphery where the inner sheet first portion and the inner sheet second portion are joined together and a central area within the periphery; c. an expansion port in fluid connection with at least one of the first primary or second primary expansion chambers (241, 242) through which the expansion material can be introduced into the expansion chamber (241, 242); and d. a closeable opening into which the one or more articles may be inserted, the opening extending from an exterior of the package to the article reservoir; wherein the package when expanded has a generally parallelepiped shape, characterized in that the expandable shipping package further comprises: e. a flexible secondary outer sheet at least partially joined to the outer sheet outer surface to form a plurality of secondary expansion chambers.