The Anglesey site has been permitted to continue using one reactor, transferring partially used fuel from Reactor 2 to Reactor 1.
Reactor 2 was shut down in April because of limited fuel stocks.
Approval for this move comes from the Office for Nuclear Regulation and is supported by the Department for Energy and Climate Change.
Wylfa had originally planned to shut down in December 2010, but an opportunity was identified to continue producing electricity for a further period.
Nuclear Decommissioning Authority Magnox program head Brian Burnett said, "Wylfa’s continued generation is excellent news and will deliver significant additional revenue to support our clean-up mission."
Wylfa site director Stuart Law said he is look forward to working with Wylfa staff through the final phase of generation at Wylfa- the IRX phase.
