It has received a £50,000 grant through the European Maritime and Fisheries Fund, which is funded by the EU and the Welsh Government.
The project, led by Keep Wales Tidy in collaboration with Marine Conservation Society and environmental consultants Eunomia, hopes to gain a better understanding of the sources and types of litter in the environment, as well as the key challenges to tackling this global crisis at a local level.
The organisations will develop a plan to work with marine litter action groups, local authorities and higher education to tackle the issue.
Welsh Environment Minister Hannah Blythyn said: “The need to tackle marine litter, especially plastic, has become part of our collective consciousness through documentaries such as BBC’s Blue Planet.
“I’m happy to support this project, which will help co-ordinate our efforts in Wales and contribute towards finding solutions to the growing threat litter poses to aquatic life.”