Volunteers carrying out a Lake District litter pick have described the mounds of rubbish as heartbreaking.
Discarded camping equipment, cans of nitrous oxide, cutlery and leftover food have been collected, while some areas have had trees cut down.
The lakes have proved popular with visitors following the recent easing of coronavirus lockdown measures.
Charity Friends of the Lake District had appealed for people to take part in the two-day clean-up across Cumbria.
Engagement officer Ruth Kirk, who paddled out to an island at Thirlmere on a kayak, said: "It just breaks my heart. It makes me want to cry.
"It's been replicated right across the Lake District, particularly around the lake shores.
"It's understandable people want to spend time here, but it has created quite a problem with the amount of litter left behind.
"It's difficult for communities. They live here and want it to be a lovely place. They don't want to have to go out as volunteers to collect litter every week."
The organisation is urging visitors not to camp at lakesides or on nearby islands and to "enjoy the landscape responsibly" by taking all rubbish home.
Some of the larger items found as part of the pick will need to be collected by rangers in boats, Ms Kirk added.
During the months in lockdown, police and park authority rangers sent home hundreds of people found illegally camping and holding parties.
Problems have continued after the easing of restrictions, though, and some locals have set up their own group to collect rubbish.