Santiago "Santi" Arias Naranjo (Spanish pronunciation: ; born 13 January 1992) is a Colombian professional footballer who plays as a right back for Spanish club Atlético Madrid and the Colombia national team.
Arias was a youth product of the La Equidad academy. He was moved into the senior squad during 2009 making his professional debut that same year against Deportes Tolima. He soon became a regular for the Bogotá based club and racked up 28 appearances. His notable performances earned him the opportunity to represent his nation at the 2011 FIFA U-20 World Cup hosted in Colombia. After a successful spell at his club and internationally, he soon moved to Portugal to join the ranks of Lisbon team Sporting CP.
While representing the U20 national Colombian side in 2011, Arias attracted the scouts of Sporting CP. On 1 July 2011, Arias was ultimately signed by Sporting on a 5-year contract for a transfer free of €300,000. He made his European debut on 6 November replacing Matías Fernández in the 80th minute against U.D. Leiria. Despite making his first team debut, Arias spent most of his playing time with the B-Squad where he scored a goal in 28 appearances. He occasionally made appearances with the first squad, but never broke in for a permanent spot.