Four sites on the banks of the River Medway are being cleared of rubbish by teams of volunteers.
Work to clear the riverbanks was being done at low tide
The annual clean-up operation is taking place during low tide at Halling, Lower Upnor Beach, Rochester Esplanade, and the Riverside Country Park.
Mark Loos, from the Medway and Swale Estuary Partnership, said it would make the river safer and more attractive.
Last year's event saw three skips and three open rubbish trucks filled to the brim, he said.
But he added: "The river's tidal patterns and the mobile nature of much the rubbish are enough to ensure that the fight is far from over."
He said the Medway was the longest river in Kent, passing through Tonbridge, Maidstone, and Rochester as well as many smaller towns and villages.
Wildlife on the river includes shelduck and oystercatcher birds, fish such as herring and perch, and protected mammals such as otter and water voles, he added.
Sites at Halling and Lower Upnor were being cleared on Saturday afternoon, and sites at Rochester and the Riverside Country Park are being cleared on Sunday afternoon.