The group built a bridge across Blo' Norton fen in 2005
A footbridge is being built which will link two areas of wetland in Norfolk and Suffolk.
The bridge across the Little Ouse near Diss is the second to be built by volunteers from Little Ouse Headwaters Project (LOHP).
It manages Betty's and Blo'Norton fens in Norfolk and is restoring Bleswycks Bank and Parkers Piece in Suffolk.
LOHP said the bridge will help improve access for walkers along the Little Ouse valley.
The 12m-long bridge will not open to the public until access works and safety measures are in place in a few weeks, it added.