Having joined the Euskaltel–Euskadi team – alongside brother Gorka – from the 2011 season onwards,[11] Izagirre won his first professional races in the spring of 2012; he won the individual time trial at the Vuelta a Asturias in April,[12] before taking a victory during his Grand Tour début at the Giro d'Italia.

He started the final stage sixth on general classification but overhauled race leader Sergio Henao (Team Sky) and the others above him by virtue of a superior time trial performance on the rolling 25-kilometre (16-mile) circuit.

He was the team's GC leader at the Tour de France, but crashed out on Stage 1, an individual time trial in Düsseldorf, suffering a lumbar fracture which ended his season.

[18] In his first year with Astana, Izagirre won the overall titles of the Tour of the Basque Country and the Volta a la Comunitat Valenciana as well as the final stage of Paris–Nice.

In June 2021, he won his second national time trial championship, before signing an initial one-year contract to ride for Cofidis in 2022 three months later.