On a typical day, a mobile knowledge worker may cross in and out of several disparate organizational contexts, confront the gatekeeping of multiple networked systems and security mechanisms, and grapple with subtler large-scale public infrastructures, such as power and transportation, in order to carry out his or her job effectively. Moreover, this worker will do this all while interacting with coworkers and clients, many of whom are also often on the move, traversing different, sometimes competing, sets of boundaries themselves. The mobile worker’s aim, as in most examples of cyberinfrastructure, is to achieve a functional seamlessness–that is, to maintain a sociotechnical exterior that suggests careful, even carefree, composition to both clients and collaborators. The achievement of these operational forms of “seamlessness,” in both material and practical terms, we call infrastructural competence. This paper develops the notion of infrastructural competence as an elemental form of modern day knowledge work.