Fidalgo debuted for Portugal U19 on February 22, 2011 in a win against Finland U19 for the 2011 UEFA Women's Under-19 Championship Qualifying Round. She also represented Portugal at the qualifying stages of the 2012 UEFA Women's Under-19 Championship and the 2013 UEFA Women's Under-19 Championship. On September 26, 2013, Fidalgo debuted for the Portuguese Senior Team in a win against Greece, a 2015 FIFA Women's World Cup qualification's match. Since then, she represented Portugal in several international competitions including the qualifying stages for the UEFA Women's Euro 2017 and the 2019 FIFA Women's World Cup. On July 6, 2017, Fidalgo was called by coach Francisco Neto to represent Portugal at the UEFA Women's Euro 2017, the first time the Portuguese team reached the final stage of a big international tournament. She didn't play in any matches as her team was eliminated while still in the Group Stage.