[4] Months before becoming Bishop of Zamora, Uriarte, in January 1991, together with the bishop of Bilbao Luís María de Larrea, issued the pastoral letter "Brothers and friends of the prisoners", in which both denounced the "illegal" conditions in which the imprisoned members of the terrorist group Euskadi Ta Askatasuna (ETA) were being held, describing them as "political prisoners", stating that "neither goodwill nor pure generosity are enough.

[1][7] Uriarte was appointed bishop of San Sebastián on 13 January 2000, and was consecrated on 27 February, succeeding José María Setién.

[2] In 2007 he interceded with the Government of José Luis Rodríguez Zapatero to mitigate the prison regime of ETA member Iñaki de Juana Chaos.

[2] When ETA announced the ceasefire in March 2006, Uriarte offered the Church's willingness to contribute to the pacification process and called to impose the "hope for peace" over "fatalism" after the 2006 Madrid–Barajas Airport bombing that put end to the truce.

[1] In November 2009, Pope Benedict XVI accepted his resignation, for reasons of age, and was succeeded by José Ignacio Munilla.

[4][8] In 2013 Uriarte demanded that ETA "disarm and dissolve", and that the Spanish Government "sweeten the prison policy to prevent the process from rotting".

[9] In an interview in March 2022, Uriarte stated that the Basque conflict will be closed "when generations have passed" and that "the weapons have fallen silent, but reconciliation is more than the peace of arms: it includes memory, truth, justice, dialogue and request for forgiveness".