Ramdin began playing cricket as a fast bowler but took up wicket-keeping because he was bored when not bowling. According to Ramdin he did not receive much coaching early in his career, though he did have sessions with David Williams and Jeff Dujon in which he worked on his wicket-keeping. He has captained both the West Indies' and Trinidad's Under-19 teams.

When the West Indies toured Sri Lanka in July and August 2005, the 19-year-old Ramdin was the only wicket-keeper in the 15-man squad, taking over from the incumbent Courtney Browne. Brown did not play international cricket after he was replaced by Ramdin and retired later that year at the age of 34. At the time of his selection, Ramdin had played in just first-class games of experience with three scores above fifty including one century. On Test debut Ramdin scored 56 runs before he was bowled by Gayan Wijekoon who was also playing his first Test. The West Indies embarked on the tour with only three of their first choice players (aside from captain Shivnarine Chanderpaul the rest of the West Indies players had just one Test century between them) because of a dispute over sponsorship and as expected lost both Tests. The Indian Oil Cup 2005 with Sri Lanka and India followed the Tests and Ramdin played his first ODIs in the tournament.

The West Indies toured Australia in October and November 2005. Australia, rebuilding after losing the Ashes earlier that year, won all three Tests. The West Indies did not register a century partnership until the fourth innings of the series when Ramdin, who scored 71, combined with Dwayne Bravo in just his seventh Test. In his five other innings in the series Ramdin managed a total of 100 runs, finishing with an average of 34.20 and scoring more runs in the series that his Australian counterpart Adam Gilchrist. During the series he received advice from Gilchrist and former Australian Test 'keeper Ian Healy regarding his batting and keeping. The West Indies next engagement was against New Zealand in February and March 2006. Of the nine international matches on the tour – three Tests, five ODIs, and a Twenty20 International – the West Indies won a single ODI and drew one Test, while New Zealand won the rest. Ramdin managed just 33 runs in the Tests, and 92 runs in the ODIs However such was Ramdin's importance to the side that he was one of seven players the West Indies Cricket Board were considering to take over as captain when Shivnarine Chanderpaul resigned from the position in April.

At this time Ramdin was competed to be first-choice wicket-keeper spot to Carlton Baugh in ODIs. Ultimately, only Ramdin was selected for the 2007 World Cup. However, Ramdin went on to cement his place as the West Indies wicket keeper in all forms of the game and was the vice-captain at one point, following the resignation from that position of Ramnaresh Sarwan. Ramdin scored his maiden Test century against England in the fourth Test at Barbados in 2009, going on to score 166 in a drawn match. He hit two centuries in the 2009–10 Regional Four Day Competition in the West Indies, at an average of 113.33, amassing 340 runs in 6 innings.

When South Africa toured in May and June 2010 Ramdin managed 63 runs in the three-Test series and 34 runs from five ODIs. The run of poor form meant Ramdin's central contract with the West Indies Cricket Board (WICB) was not renewed in August 2010.