A product of hometown CA Osasuna's youth system, Flaño was born in Pamplona, and he made his debut with the first team in a La Liga 2–1 home win against Villarreal CF on 28 August 2005, going on to finish his first season with 31 games.
Flaño, who originated from Osasuna's youth system, was born in Pamplona and made his professional debut for the club in a La Liga match against Villarreal CF on August 28, 2005. He played 31 games during his first season.