St George Illawarra have signed halfback Sam Williams from Canberra on a one-year NRL deal starting in 2014.

Williams had been strongly linked to the Dragons after failing to play regular first grade this year with the Raiders, after starring in their charge to the finals last season.

The Dragons couldn't put together a deal for Williams before the June 30 deadline, meaning he can't play for them this season but he will add some much needed spark to the joint venture's attack next year.

Williams will join Melbourne playmaker Gareth Widdop in the halves for the Dragons in 2014.

A former Raiders rookie of the year, Williams appears to have fallen out of favour at Canberra with Terry Campese and Josh McCrone coach David Furner's preferred halves combination.

The 22-year-old Williams will join the Dragons in November ahead of the 2014 NRL season with an option for a second season in 2015.

He has played seven games for Canberra this year and will feature in the NSW Residents side against Queensland Residents in the curtain raiser to Wednesday's State of Origin decider.