The National Trust has said this year's Easter egg hunts will be the last with Cadbury as it seeks to focus on "nature and the outdoors".
Annual egg hunts have taken place for 13 years, but the trust said it wanted to make chocolate "less of a focus".
Health campaigners said they "applaud" the trust for ending the "unhealthy association" with sugary food.
Cadbury said they had come to a mutual decision to end the "wonderful" partnership.
The move will affect hundreds of trails through the grounds of National Trust properties across England, Scotland, Wales and Northern Ireland from 2021.
The trust said: "Now is the time for change as we look to increase our emphasis on nature and the outdoors.
"To reflect that in our Easter activities, from next year we will be making chocolate less of a focus."
Cadbury said "the time is right for both sides to move on". But the company said it would continue to "look for ways to bring Easter trails to more families across the UK".
'Nudges towards snacks'
Barbara Crowther at the Children's Food Campaign said she was "really pleased" that the National Trust was moving its Easter activities away from chocolate.
"We can imagine so many healthy, fun and active ways for children to explore National Trust properties at Easter that don't involve lots of sugary treats," she said.
"Children are growing up in a marketing environment that constantly nudges them towards snacks and treats, so we applaud the National Trust in recognising it is the right time to end the unhealthy association with chocolate."
The Easter egg hunts have proved controversial in the past, with former Prime Minister Theresa May and the Archbishop of York intervening in 2017 to criticise the apparent absence of the word "Easter" from the event marketing.
Both Cadbury and the National Trust said Easter was explicitly mentioned dozens of times.
And in 2018, the chocolate manufacturer's partnership with the National Trust for Scotland was deemed to have broken advertising rules over marketing junk food to children.