Dias is a former Portugal youth international, representing his country at under-16, under-17, under-19, under-20 and under-21 levels. He made his senior international debut in 2018, being chosen in Portugal's squads for the 2018 World Cup, 2019 UEFA Nations League Finals and UEFA Euro 2020; he won the 2019 tournament on home soil, while also being named as the man of the match in the final.