Prati also played for the Italy national football team. He was most notably a member of the Italian side that won the 1968 UEFA European Football Championship on home soil, during which he made his debut on 6 April, scoring a goal in a 3–2 loss against Bulgaria in the first leg of the quarter-finals, and another in the 2–0 victory in the return leg. He played the first final match alongside Pietro Anastasi, but was replaced by Luigi Riva in the re-match, the striker who would often keep him on the bench for Italy. With his national team, Prati also reached the final of the 1970 FIFA World Cup, losing out to Brazil. In total, he was capped 14 times for the national side between 1968 and 1974, scoring 7 times.