Port-injection footwear is provided. In one example, port-injection footwear is provided including a footwear-structure bag encompassing an injected filler material, such as foam. A strobel sock made of stretchable material may be integrated into an insole region of the footwear-structure bag. The port-injection footwear further may include a foam barrier disposed adjacent to the footwear-structure bag to retain the injected foam within the bag during injection. An outsole may be directly coupled to the footwear-structure bag forming a base of the footwear article. In other examples, the port-injection footwear may include a footwear-structure bag having an injection port, an injected foam retained in the footwear-structure bag, where the injected foam was injected through the injection port, and a port cap positioned at the injection port of the footwear-structure bag.