Aitor Seguín

Born in Eibar, Gipuzkoa, Basque Country, Seguín joined Athletic Bilbao's youth setup in 2005, aged ten. He made his debut as a senior with the farm team in the 2012–13 campaign, in the fourth tier. On 26 May 2014, after scoring 11 goals for Basconia, Seguín was promoted to the reserves in Segunda División B. He appeared in 35 matches and scored three goals over the course of the season, as the B-side returned to Segunda División after a 19-year absence, via the play-offs. Seguín made his professional debut on 24 August 2015, starting in a 0–1 home loss against Girona FC. He scored his first goal in the second tier on 6 September, netting his team's second in a 3–1 home win against RCD Mallorca. In April 2016, having been involved in the majority of the season's fixtures and scored two further goals, Seguín suffered a rupture of the anterior cruciate ligament in his right knee, requiring a lengthy rehabilitation. He returned to the team nine months later at the end of January 2017, but only made seven appearances as a late substitute before the end of the campaign, having undergone minor keyhole surgery on the injury in March. Seguin featured in two of the first three games of the 2017–18 season, but reported injured in September and did not play again in the calendar year. Similar injuries were endured by Iker Undabarrena, Seguín's long-time teammate (he also joined Athletic's academy as a 10-year-old in 2005) which hampered the development of both players and damaged their…

Seguín's elder brother Iker Seguín is also a footballer and a left winger by position; he also spent some time with Athletic Bilbao's reserves, later serving as captain of SD Amorebieta when they were promoted to the second tier in 2021.