He played and scored for the reserve team in the North-Eastern League,[3] and on 23 January 1932, he made his first-team debut and scored in a 6–3 win against local rivals Hartlepools United in which "Wellock, Grieve and Coates shot at every conceivable opportunity, on the half turn, the volley, the half-volley, and on occasions when their backs were turned to the goal".
In September, Coates was included in the Rest of the North-Eastern League team for the annual fixture against the reigning champions, in this case Middlesbrough Reserves.
[14] In May 1937, the long-serving secretary-manager of Spennymoor United, Charles Sutton, resigned to take up the position of manager of another North-Eastern League club, Horden Colliery Welfare.
[15] He went one better with his new club, finishing a point ahead of Sunderland Reserves at the top of the 1937–38 North-Eastern League, and accepted terms for the coming season.
[13] Once eliminated from the Cup, Coates received – and rejected – an offer of first-team football from Second Division club Bradford, preferring to continue as a part-timer with Horden.