A shoulder bag has a first pocket having a front and a back panel joined along lower edges and side edges, the first pocket open at upper edges of the front panel and the back panel, the first pocket having a first width and a first height, a second pocket having a second front panel and a second back panel joined along lower edges and opposite side edges, the second pocket open at adjacent upper edges of the second front panel and the second back panel, the second pocket having the first width and the first height, and a shoulder region connecting the first back panel of the first pocket and the second back panel of the second pocket. Fabric strips are attached at ends of the strips to regions of the first and second pockets to extend outside the pockets and restrict openings of the pockets.

A combination bag, includes a sling bag and a backpack with an interior space, wherein the sling bag includes: a flat-shaped and foldable bag body with a first surface and a second surface, a rigid support structure embedded within the flat-shaped bag body, symmetrically arranged along a fold line of the flat-shaped bag body; a shoulder strap attached to the flat-shaped bag body; at least two bag components positioned on the second surface of the flat-shaped bag body, for forming an independent storage compartment; and the interior space is defined by a first wall, a second wall opposite the first wall, and a continuous side wall connecting the first and second walls; wherein the first wall has an area approximately equal to that of the flat-shaped bag body, and flat-shaped bag body is detachably fixed and close contacted with the first wall by a connecting component.