Foster rejoined Conference Premier side Lincoln City on 1 August 2013, signing a one-year deal with the club he had previously played for from 2005 to 2007. He made his second debut for the club ten days after signing, on the opening day of the 2013–14 season, playing the whole match in central defence as Lincoln drew 0–0 away at Woking. Both of Foster's goals for the season came in away fixtures at Braintree Town. The first was scored in an FA Trophy match on 14 December 2013, netting in the 91st minute to give Lincoln the lead in an eventual 3–1 win. His second came in the same fixture, but in the league, three months later; courtesy of a header from a Sean Newton corner in a 2–0 away victory on 18 March 2014. He featured regularly throughout the campaign, making 37 appearances in a season where Lincoln struggled for consistency and finished 14th in Conference Premier. Foster left Lincoln when his contract expired at the end of the season.