Early representation

On 7 June 2008, Roach was selected in the West Indies Test squad to face Australia in the third Test. At the time he had played in only four first-class matches. He was not picked for the final team and said "I know that when a Test match comes around, they sometimes draft in players in the island where the match is, but I wasn't expecting to be in the squad. I'm quite happy to be there. If selected, I want to put in a good performance". Roach made his international debut on 20 June 2008 in a Twenty20 international against Australia; it was also the first senior Twenty20 match he had played in. He finished with the best bowling figures in the match of 2/29 from three overs, claiming the scalps of Shaun Marsh and Luke Ronchi as the West Indies won by seven wickets. Roach was drafted into the squad for the last two ODIs against Australia in July 2008 after Australia won the first three games and sealed a series victory.

Roach did not play in the last two matches of the series against Australia and had to wait until the triangular series with Bermuda and Canada to make his debut. On 20 August 2008 Roach – along with fellow debutants Leon Johnson and Brendan Nash – made his first appearance for the West Indies in a One Day International. He finished with figures of 10–1–29–2 as the West Indies beat Bermuda by six wickets. His first wicket was that of Steven Outerbridge and his second was the Bermuda captain, Irving Romaine. He played in the second match of the series, taking 1/49 from eight overs against Canada as the West Indies won by 49 runs but did not play in the final against Canada which the West Indies won.

On 1 November 2008, the ODI squad to tour Pakistan was announced, with Roach as one of the members. John Dyson, the West Indies coach, said that Roach was expected to put the more experienced and established bowlers such as Fidel Edwards and Jerome Taylor under pressure for a place in the team. On the same day, it was announced that Roach was one of four players – along with Lionel Baker, Leon Johnson, and Brendan Nash – without a Test cap to be named in the 15-man squad selected to tour New Zealand for a Test series.

Breakthrough

Roach made his Test debut on 9 July 2009. He was part of an understrength team fielded by the West Indies against Bangladesh; in the 15-man squad, there were nine uncapped players and in the Test seven West Indies players made their debut. The side was captained by Floyd Reifer who had played the last of his four Tests ten years earlier. The first XI had made themselves unavailable due to a pay dispute with the West Indies Cricket Board. His first Test wicket was that of all-rounder Shakib Al Hasan. Although Bangladesh won by 95 runs, Roach helped put pressure on the Bangladesh batsmen through a combination of yorkers and swinging deliveries, although he bowled slightly wide to the left-handers.