The sand spits (pontas) are distinctive land forms of the Tapajós riverside landscapes, in the Lower Amazon (Brazil). Mostly due to the annual flood of the river, their shape is in continuous transformation. As visual, practical and cognitive saliencies, these sand spits are characterized by a hybrid nature, between dry and wet, land and water, emerged and submersed, visible and invisible. As such, they appear to be situated in an 'in-between: between two elements (water/land, land/sky, water/sky), two floods (dry/rainy, submerged/emerged), two worlds (on-earth/underwater, human/nonhuman) and two times (past/present, present/future). In a renewed framework of studies on the relations between societies and their environment, the landscapes are no longer considered as mere backdrops on which social activities unfold. Following this statement, I will carry out a relational study of the Amazonian concept of pontas as it is perceived and lived by the inhabitants of the river Arapiuns, an affluent of the Tapajós river. I will show how the pattern of interactions between the several human and non-human collectives of “owners” (donos) that co-reside in peculiar sand spits shapes the way people relate to places. Changes in the landscape ensuing from these interactions induce mobilities of people and of non-humans across the river, legitimizing territorial occupations of specific groups over time and hierarchizing differentiated rights of access. In a region where up to now there has been no satisfactory land tenure regularization, the transformations of the landscape echo the forms of ownership over the land.