Litter abundance and typology were investigated at different beaches and mangrove forests at nine sites on the Colombian Caribbean and Pacific coasts. Average litter abundance on the Caribbean Sea beaches (1.42 items/m 2–12.21 g/m 2) and in mangrove forests (1.29 items/m 2–28.72 g/m 2) were greater than that of the Pacific Ocean beaches (0 items/m 2–0 g/m 2) and mangrove forests (1.13 items/m 2–79.41 g/m 2). The most abundant litter material was plastic, which represented 93.61% of the total litter content. According to the Clean Coast Index, the sites analyzed in the Caribbean Sea were “Moderate” to “Extremely Dirty”, while those in the Pacific Ocean were “Clean” to “Moderate Dirty”. The Magdalena River is considered the main source of litter on the Caribbean Sea coast, while on the Pacific Ocean coast, litter is essentially associated with the mismanagement of solid wastes. This study constitutes a baseline on the litter content of beaches and mangrove forests, and is useful for establishing sound strategies for their protection, restoration and conservation.