 On 19 November 2009, Coulson signed for League Two club Grimsby Town on an initial one-month loan.He made his debut two days later after starting in a 0–0 draw away to Lincoln City.He scored his first goal for Grimsby on 5 December 2009 in his fourth appearance, a 1–1 home draw with Dagenham & Redbridge, opening the scoring in the 36th minute before Dagenham equalised in the second half.