Simple Prepositions in Irish

Overview

Prepositions are small words that express relationships between things — location, direction, possession, time, and more. Irish has a set of about twelve simple prepositions that you will use constantly from the A1 level onward. These single-word prepositions are the building blocks for expressing where things are, who things belong to, and how actions relate to each other.

What makes Irish prepositions special is that they interact with the grammar around them in powerful ways. They trigger mutations (lenition or eclipsis) on following nouns, they combine with the article an to form special contracted forms, and — most distinctively — they merge with pronouns to create unique prepositional pronouns (e.g., ag + mé = agam).

Learning the simple prepositions and their mutation effects is one of the most practical things you can do at this stage, because they appear in countless everyday expressions.

How It Works

The twelve common simple prepositions

Irish	English	Mutation triggered
ag	at	—
ar	on	lenition (in some cases)
as	out of	—
de	of, from	lenition
do	to, for	lenition
faoi	under, about	lenition
i	in, into	eclipsis
le	with	—
ó	from	lenition
roimh	before	lenition
thar	over, past	—
trí	through	lenition

Prepositions with the article

When a simple preposition meets the article an, they often merge:

Preposition + an	Combined form	Example
i + an	sa / san	sa teach (in the house)
de + an	den	den chéad uair (for the first time)
do + an	don	don fhear (for the man)
ó + an	ón	ón siopa (from the shop)
le + an	leis an	leis an mbean (with the woman)
ag + an	ag an	ag an doras (at the door)

Examples in Context

Irish	English	Note
ar an mbord	on the table	ar an + eclipsis (standard)
i dteach	in a house	i + eclipsis
le Máire	with Máire	le — no mutation
ó Bhaile Átha Cliath	from Dublin	ó + lenition
sa teach	in the house	i + an = sa
ag an doras	at the door	ag an — no change or eclipsis
do Sheán	for Seán	do + lenition
faoi bhun	underneath	faoi + lenition
trí Ghaeilge	through Irish	trí + lenition
roimh Nollaig	before Christmas	roimh + lenition

Common Mistakes

Forgetting mutations after prepositions

• Wrong: i teach (without eclipsis)
• Right: i dteach
• Why: The preposition i triggers eclipsis. The t becomes dt.

Confusing de and do

• Wrong: Tabhair do Sheán é when you mean "from Seán"
• Right: Tabhair do Sheán é (Give it to Seán) vs. Fuair mé ó Sheán é (I got it from Seán)
• Why: Do means "to/for" while ó means "from." The older preposition de means "of/off" and is different again.

Using English preposition logic

• Wrong: Tá mé ag an obair (at work — calquing English)
• Right: Tá mé ag obair (I am working) or Tá mé san oifig (I am in the office)
• Why: Irish prepositions do not always map directly to English ones. Learn which preposition goes with which phrase.

Practice Tips

1. Learn the twelve simple prepositions as a list and practice them with concrete nouns: "ar an mbord," "i dteach," "le Máire." Physical objects and places make prepositions memorable.
2. Focus first on ag, ar, i, le, and ó — these five appear in the majority of everyday sentences and will give you the most immediate benefit.

Related Concepts

• Prepositional Pronouns — what happens when prepositions combine with pronouns
• Location and Directions — using prepositions to describe where things are
• Prepositions with the Article — the contracted forms in detail
• Compound Prepositions — multi-word prepositions for advanced learners