under coach marcello lippi, šimić had his serie a debut in a 2–0 win against venezia at san siro on 10 january 1999. by the end of his first season in italy, šimić earned a total of 17 appearances and scored 2 goals for internazionale. in the following couple of seasons šimić's services were regularly used, until the 2001–02 season, when he had only 12 league and 8 european appearances. and in june 2002 internazionale and their cross-city rivals ac milan agreed a player swap with ümit davala going in the opposite direction, which šimić was valued €16.5 million, despite it was purely accounting purpose. in his three and a half years with internazionale he earned a total of 66 league appearances and scored 3 goals. the club failed to win any silverware in this period, and their highest finish was fourth place in the 1999–2000 season, even though this was the time when some of football's biggest stars played there with šimić, such as roberto baggio, ronaldo, ivan zamorano, diego simeone and christian vieri.