This paper is motivated by a methodological interest in how to investigate information infrastructures as an empirical, real-world phenomenon. We argue that research on information infrastructures should not be captive to the prevalent method choice of small-scale and short-term studies. Instead research should address the challenges of empirically studying the heterogeneous, extended and complex phenomena of infrastructuring with an emphasis on the necessarily emerging and open-ended processual qualities of information infrastructures. While existing literature identifies issues that make the study of infrastructuring demanding, few propose ways of addressing these challenges. In this paper we review characteristics of information infrastructures identified in the literature that present challenges for their empirical study. We look to current research in the social sciences, particularly anthropology and science and technology studies (STS) that focus on how to study complex and extended phenomena ethnographically, to provide insight into the study of infrastructuring. Specifically, we reflect on infrastructuring as an object of ethnographic inquiry by building on the notion of “constructing the field.” Recent developments in how to conceptualize the ethnographic field are tied both to longstanding traditions and novel developments in anthropology and STS for studying extended and complex phenomena. Through a discussion of how dimensions of information infrastructures have been addressed practically, methodologically, and theoretically we aim to link the notion of constructing the ethnographic field with views on infrastructuring as a particular kind of object of inquiry. Thus we aim to provide an ethnographically sensitive and methodologically oriented “opening” for an alternative ontology for studying infrastructuring ethnographically.