The duo was found establishing a home in restored wetlands at Pensthorpe Nature Reserve.
Just a few months ago, one beaver was spotted at the site.
There was initially believed to be one beaver in the wild in Norfolk (Image: Pensthorpe)
They were originally thought to be alone, but camera footage has now shown two beavers engaging in grooming behaviour and occupying a substantial lodge on a remote part of the reserve.
Their presence marks the first wild pair recorded in the county for several centuries.
Richard Spowage, reserve manager at Pensthorpe, said: “When we confirmed a single wild beaver last autumn, it marked a historic return for Norfolk.
“To now confirm a settled pair with an established lodge changes the scale of that moment entirely.
Now, another has been spotted on camera (Image: Pensthorpe)
“A pair occupying a lodge indicates stability and suitable habitat.
“It suggests this landscape is not simply being explored, but is capable of sustaining a native species absent for centuries.”
The beavers are living entirely naturally and are not part of a release programme.
Their impact so far has been positive, with evidence of reduced silt and debris movement through the channel, exposure of sand and gravel along sections of the river bed and more varied in-channel habitat.
The pair have been knawing on trees and swimming around (Image: Pensthorpe)
Pensthorpe does not know where they came from.
Mr Spowage said: “The fact that beavers are appearing in multiple suitable landscapes across the country inevitably raises wider questions about how Britain manages the return of native species.
“Landscapes that are restored and connected will support wildlife.
“The key challenge now is ensuring national policy keeps pace with ecological reality.”
Beavers were hunted to extinction in Britain during the 16th century, but recent licensed reintroduction schemes and natural dispersal have seen their gradual return.
Pensthorpe has notified government agencies, including Natural England, and is working with partners and nearby landowners.
The animals are not being promoted as a visitor attraction and sightings remain extremely unlikely.
For welfare reasons, the exact location of the beaver lodge is not being disclosed.