The purpose of this paper is to assess the extent to which regions’ absorptive capacity determines knowledge flows’ impact on regional innovation intensity. In particular, it looks at the role of the cross-regional co-patenting and mobility of inventors in fostering innovation, and how regions with large absorptive capacity make the most of these two phenomena. The paper uses a panel of 274 regions over 8 years to estimate a regional knowledge production function with fixed-effects. Network and mobility variables, and interactions with regions’ absorptive capacity, are included among the r.h.s. variables to test the hypotheses. We find evidence of the role of both mobility and networks. However, inflows of inventors are critical for wealthier regions, while have more nuanced effects for less developed areas. It also shows that regions’ absorptive capacity critically adds an innovation premium to the benefits to tap into external knowledge pools. Indeed, the present study corroborates earlier work on the role of mobility and networks for spatial knowledge diffusion and subsequent innovation. However, it clearly illustrates that a certain level of technological development is critical to take advantage of these phenomena, and therefore one-size-fits-all innovation policies need to be reconsidered.