Residents of Llandudno in North Wales want their beach restored to its former sandy state after 50,000 tonnes of rock was put there.
The rocks were deposited on North Shore beach by Conwy County Borough Council in 2014 with the aim of reducing flooding.
But the action “destroyed the beach”, according to a petition to have the rocks removed.
The petition was started by Llandudno councillor Ian Turner and has now gained more than 10,300 signatures.
Campaigners want sand restored to the beach controlled with timber groynes, at a cost of about £24m.
“Access for many is almost impossible, and dangerous if people try,” the petition reads.
“It’s a blight on the landscape, and detrimental to our main economy tourism.”
The petition will be considered for debate by the Welsh Parliament’s Petitions Committee after reaching the threshold of 10,000 signatures.
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One of the campaign’s backers, Conservative Senedd member Janet Finch-Saunders, said the North Shore beach was a “location of major importance”.
“One of the UK’s leading destinations, and the queen of Welsh resorts deserves a sandy beach,” she said.
“With boulders on the beach, people are unable to enjoy using the foreshore like they used to. It is dangerous, and inaccessible to many.”
Last August, the Welsh government rejected the council’s proposal to replace the rocks with sand.
It said the cost was not justifiable when the same level of flood protection could be achieved for less than a third of the cost by raising the promenade wall.
The council’s cabinet then agreed to support a non-sand flood defence option for the beach.