Abstract: A collapsible, foldable breach bag with a planar body and a flexible fillable bladder for breaching locked or barricaded doors or penetrating surfaces with explosive charges. The breach bag is generally cylindrical and includes an interior wall and an exterior wall, joined at their respective upper and lower edges so as to form a tube with space apart interior and exterior sides. A flexible fill spout with a flexible material connection to an upper portion of the exterior wall enables detonation of the bag without producing a dangerous projectile. Material attributes and dimensions enable the bag to capture and secure a length of det cord disposed through the interior passage when the bag is filled with fluid. Air pockets may be urged out from the interior volume using the fill spout, and the fill spout may then be clamped or tied off and secured to a structural surface.