In 2019 with the Nationals he batted .250/.300/.447. Between the Giants and the Nationals combined, in 2019 he batted .234/.293/.391 with nine home runs and 48 RBIs in 274 at bats. During his time with the Nationals, at the suggestion of his children, Parra changed his walk-up music to the popular children's song "Baby Shark". This became a crowd favorite throughout the second half of 2019, as crowds at Nationals Park began to sing along and do the accompanying motions whenever Parra came up to bat. Fans throughout the stadium were seen doing the "shark dance" when Parra was called up to bat in Game 4 of the 2019 National League Championship Series, and then again when Parra was called up to pinch-hit in Games 3, 4, and 5 of the 2019 World Series vs. the Houston Astros. The Nationals won the World Series in 7 games, their first in franchise history.