After a trial with the club, Vignal joined Southampton on a season-long loan on 27 July 2007. He scored his first goal for Southampton with a free kick in a 2–0 win over Leicester City in the FA Cup, and his first league goal came from a penalty against Scunthorpe United while playing with a broken arm. He scored another penalty in the 2–2 draw with Wolverhampton Wanderers before being sent off for an off-the-ball incident. However, he later won an appeal against the card. He scored four goals from 23 appearances in the 2007–08 season.