This article analyzes new co-innovative sources of firm labor productivity. Using survey data for 120 small and medium-sized travel agencies based in Catalonia (a region in the northeast of Spain) and partial least square–structural equation modeling (PLS-SEM) estimation techniques, three main findings emerged from the study. First, labor productivity is directly explained by those agencies’ capacity to exploit their assets, to use local networks, and to make international transactions. Second, the analysis of indirect effects on labor productivity suggests a circular causality, which is determined by the influence of the workers’ local network use on a firm’s export capacity. In this circular relationship, a firm’s capacity to generate market-leading product innovations and the stock of human capital and training play a decisive role. Third, co-innovation practices exert a negative effect, which may be related to difficulties in terms of securing productivity improvements in the short term.