Hola Alvaro, I am not a teacher but I think in Ireland people who want to teach in primary school (escuela) usually go to a teacher training college and study for a Degree in Education. But they can also study for another degree (usually Mathematics or Arts/Humanities; like English, French, History...) and then they can do a Higher Diploma in Education (known as a H.Dip) I think it is similar in the United Kingdom. In Ireland to teach in Primary school you also need to be able to speak Irish (Gaelico). For secondary school (instituto), I think most peole study a normal degree (this could be in anything but it is obviously better if it is in the subject that the person will teach) and then do a Higher Diploma in Education (known as a H.Dip). I think the Higher Diploma in Education is different depending on if you want to teach in Primary or Secondary School si quieres, puedes leer más aquí : http://www.teachingcouncil.ie/teacher-education/initial-teacher-education-ite.191.html or http://www.education.gov.uk/get-into-teaching/teacher-training-options.aspx Espero que esto ayude. Lo siento que es todo en inglés.