Born in Errenteria, Gipuzkoa, López joined Athletic Bilbao's youth system in 2011 at the age of 14 from neighbouring Real Sociedad, after starting out at Antiguoko.
[7] He made his first-team debut the following day, coming on as a substitute for Markel Susaeta in the 72nd minute of a 3–1 home win and also providing an assist to Ibai Gómez in the last goal.
[11] López scored his first competitive goal for Athletic on 8 March 2020, from a free kick to open a 4–1 away league victory over Real Valladolid.
[12] He featured regularly during the 2019–20 campaign, but subsequently fell down the pecking order after the emergence of newer youth prospects such as Oihan Sancet, Unai Vencedor and Oier Zarraga.
[13] On 31 August 2021, López returned to Rayo on a three-year contract;[14] Athletic retained a first refusal clause on any future transfer, while also receiving "a series of economic compensations".