SUMMARYLiterature on environmental science and management endorses crossing boundaries between disciplines, types of organizations and countries for environmental conservation. A literature review on interdisciplinarity, interorganizational networks and international cooperation highlights their justifying rationales and strategic practices. Crossing boundaries implies substantial challenges to managing collaboration itself, notably politics and uncertainty. Challenges to collaboration become compounded when crossing multiple boundaries simultaneously, here illustrated using the case of three projects in the south-western Amazon. Strategic practices such as net brokering and organizational courtships are highly important when crossing multiple boundaries. There are important commonalities in strategic practices for crossing different boundaries, such as recognizing grievances to manage politics, constituting functional redundancies in networks to manage uncertainty and non-aligned collaboration to manage both difficulties.