In autumn of next year he went to the Seminary of Vitoria, located close to the Old Cathedral, where he studied Philosophy and Theology. He was interested in all the subjects and he devoted himself to them all intensively. At the same time and by himself, he studied Teaching.
He was particularly interested in Physics and Geology. He spent the summers, together with another student of Forestry Engineering, making excursions through the mountains of Ataun observing their geologic nature.
There was a slack period in his life until the middle of his theological studies. Studying Sociology and Sciences by himself, brought doubts to his faith, which had been sure until then. That was the main reason why he devoted himself afterwards to study the History of Religion. Once his personal problem had been solved, he did not want to become just an expert in the History of Religion.
He decided to do research by himself, considering that it was logical to begin by studying his own People, where he saw that elements from older religions, that he had learned from childhood, survived christianised. At this moment his later devotion to the investigation of the Archaeology and Ethnography of the Basque Country began.
Not satisfied by the internal peace obtained from his studies, which came in fact from catholic beliefs, he decided to contrast his ideas with those of others who had different beliefs. Therefore, he spent his summer holidays in 1913, a year before finishing his studies, at the University of Leipzig, following a course on the Psychology of the Peoples, taught by Prof. Wundt.
At the beginning of the new term in Vitoria, the last year of his studies, he was given the task of teaching History of Religion, but as a result of a sudden change in the course of study together with the absence of the official professor of Physics, he is also given the responsibility of teaching this subject provisionally, although this lasted until 1936, when the Spanish civil war put an end to his teaching at the Seminary of Vitoria.
He is ordained priest at the end of 1914 and sent to Burgos to graduate in Theology.
The following year, his father died.
At the beginning of the First World War, Barandiarán, who had made a wireless set, listened and talked about the news concerning the war before it appeared in the local press. This caused him problems like inspections by the regional authorities, who thought he was spying. After several inspections, the authority in charge of the matter was convinced that he only had a home-made receiver, which anybody could make.