He made his professional debut in 1987 with Académica de Coimbra,[1] and stayed with the Students for a further two seasons in spite of their relegation to the Segunda Liga.

After that, solid defensive performances earned him a move to Benfica for 1994–95, where Dimas continue to develop as a player, which led to a November 1996 transfer to Serie A side Juventus.

[1] He made 18 appearances in all competitions for the latter in the second half of the season, totalling 21 in the league during his first full campaign while being crowned champion in both years; however, he struggled to break into the first team permanently, and after only one match in 1998–99[2][3] he moved to Turkey on 1 October 1998 with Fenerbahçe.

[3] After a good run at UEFA Euro 2000 with Portugal (he made his first international appearance in 1995 while at Benfica, and was the nation's first choice at that and the previous continental competition, playing four games in each),[5][6] he proved he could still be of value for a title contending team, and returned home after signing for Sporting CP.

[1] After quickly losing the battle for first-choice with fellow international Rui Jorge, mainly due to a right knee injury,[1][7] Dimas was deemed surplus to requirements, moving on loan to Marseille[8] although he still helped Sporting in two matches in his second season, as the capital club conquered the double.