The site in Wylfa has been sold to RWE and E.On
Three nuclear power sites have been bought by European energy firms, the Department of Energy and Climate Change (DECC) has said.
A consortium of German power companies RWE and E.On has bought sites in Wylfa in North Wales and Oldbury in South Gloucestershire.
France's EDF Energy has bought a site at Bradwell in Essex.
The sale of the three sites is worth up to £387m to the Nuclear Decommissioning Authority (NDA), DECC said.
The NDA launched an auction of 11 potential sites last month. Money raised will be used to support its clean-up operations at nuclear sites.
"The successful outcome of this site auction is yet more evidence of major energy players gearing up for investment in low carbon energy in the UK," said Energy and Climate Change Secretary Ed Miliband.
The UK government is planning to build a new generation of nuclear power stations to replace those being decommissioned, which is seen as central to their plans to curb greenhouse gas emissions in the future.