A wildlife trust has raised the £1m needed to transform the arable land into a new nature reserve.
Suffolk Wildlife Trust said the money has allowed it to buy the land for Martlesham Wild, on the banks of the River Deben.
Previously an organic arable farm, the nearly 300-acre site will be left fallow to "create a space in which nature can recover", the trust said.
It added it was "thrilled" communities had come together to raise funds.
The trust said Martlesham Wilds would be a "substantial new nature reserve" .
"Our vision... is to create a space in which nature can recover - to allow wilder habitats to return and become homes to species such as curlew, avocet and redshank, as well as reptiles, mammals and invertebrates," it said.
It is hoped that as hawthorn, blackthorn, gorse and wild rose establish on the dry sandy soils, they will support growing flocks of linnets and yellowhammers and small mammals will "thrive in the dense undergrowth".
The trust hopes the change will encourage grass snakes, slow worms and common lizards to expand into the new areas of habitat and that the "wilded" land will become part of a "connected landscape" of ancient woodland, scrub, grassland and saltings, linked by the River Deben.
After the appeal launched in 2022, more than 2,300 individuals, community groups, and local organisations got involved with fundraising, the trust said.
Chief executive, Chris Luxton, said: "By securing this small piece of the Deben landscape, the trust makes a big step forward in helping nature in Suffolk to recover.
"Thank you to everyone who has helped make this possible."