Most of Colombian wetlands are located in the Caribbean Region. Its flood pulses are related with the existence of floodplains, which are very productive lands traditionally used by the people who live nearby, but it also have been of great interest of other actors such as cattle farmers. This work describes and characterizes the relationships that have occurred between access and use of Common Pool Resources of wetlands and floodplains and socioenvironmental conflicts occurring in Sincerin, Arjona, Boivar. To this purpose, ethnography, participative workshops, semi-structured dialogues, no structured dialogues were used. Besides, documentary, and cartographic information revision of Sincerin was performed. Wetland and its floodplains are and have been used for fishing, cropping, cattle and hunting. Historically, two type of users have shared resources: the ones who need them to survive and others who do not depend of its profit. This has occurred in a scenario in which formal institutions do not accomplish its work, giving privileges to some groups over others. Therefore, access to wetland, floodplain tenure and its customary uses are characterized by corruption, which has established as the informal institution that operates between other informal institutions and formal ones, making difficult for people to organize. As a result, there is a tragedy of the commons scenario, in which resources are affected; poverty increases and conflicts heighten amidst deepening historical inequalities.