Kromkamp made his debut for the "Reds" on 7 January 2006, in a 5–3 win over Luton Town in the third round of the FA Cup. During his stint at Anfield, however, he was unable to dislodge Irish international Steve Finnan from the starting lineup, but did make a number of appearances from the bench, most notably in the domestic cup final; he was described as being a fair crosser of the ball with a lack of pace, who had difficulty in stopping opposition wingers getting crosses in.