Once you have completed your teacher training in the U.K. You will need to complete a certificate in religious education (if you wish to teach in a Catholic Primary School) and an Irish qualification. These can both be completed while you are working.

Certificate in Religious Education
This programme can be completed part time with Mary Immaculate College, Limerick, St. Patricks College Dublin, St. Angelas College, Sligo.

Useful links
Catholic Bishops Website
Mary Immaculate College
St. Patricks College
St. Angelas NUI Galway

Irish Qualification
This programme also needs to be completed. You cannot complete your DIP without this qualification. There are two options – the SCG (Aptitude) and OCG (Adaptation Period).
All the information you need can be found here.

The SCG consists of; 

Exam 1 (essay, translation, grammar, comprehension, teaching of Irish)
Teaching in the classroom (yearly scheme, weekly scheme, lesson plan, teaching of lesson)
Aural exam (3x announcement, conversation, news passage
Exam 2 (prose and poetry)
Language and Culture Project
Oral exam (15/20 mins)
3 weeks at the Gaeltacht

(Need access to a mainstream classroom to complete teaching in the classroom section)

OCG consists of;

Written Assessment – letter, translation, grammer, reading comprehension
Aural exam (3x announcement, conversation, news passage

Oral exam (15/20 mins)
Teaching in the classroom (2 school visits, assessment of preparation and teaching of Gaeilge).

3 weeks at the Gaeltacht