Plastic pollution is a global problem that poses a threat to coastal and marine ecosystems and human livelihoods and requires effective solutions adaptable to local conditions. In Colombia, the knowledge about marine plastic pollution is still limited and the development of effective strategies for managing marine and coastal environments is crucial. Therefore, plastic pollution was assessed on 43 Colombian sandy beaches on the Caribbean and Pacific coasts. Amounts of macroplastic ranged from 35 ± 15 to 81 ± 23 items 100 m−1, being product’s packaging the most common. Microplastic densities ranged from 3 to 1387 items m−2. The highest microplastic concentrations were found on the beaches from Caribbean cities and in rural areas of Pacific municipalities. Fragments and polyethylene were the most commonly observed shape and polymer categories, respectively. Tourism and poor waste management practices are the primary plastic sources on the studied beaches. Plastic litter on Colombian beaches are a problem that requires prevention, mitigation, and control actions to help conserve this ecosystem.