On 2 June 2009, Dyer joined Swansea City on a permanent basis after the Welsh side agreed to pay a £400,000 fee to Southampton. He made his debut in the opening match of the 2009–10 season against Leicester City, playing the full 90 minutes. He scored his first goal as a permanent member of the squad, a match winning score against Sheffield United, on 26 September 2009. On 7 November 2009, Dyer scored his second goal in two matches against Cardiff City, when his header from close range helped the Swans claim a 3–2 victory in the local derby. He scored again in a 1–1 draw against Queens Park Rangers.