Using Portuguese Prepositions ‘A’ and ‘Em’ with Time: Routine vs. One-Off Events

Portuguese prepositions can take on different roles depending on the context. For example, “a” is primarily a preposition of movement, while “em” is predominantly a preposition of place. However, both can also function as prepositions of time.

In this article, we explore the use of “a” and “em” as time prepositions, focusing on situations where choosing one or the other can indicate whether we are referring to routine or one-off events. Read on.

A – Routine Events

We use “a” to refer to routine events, especially when mentioning days of the week:

Às terças-feiras tenho aula de Português.
On Tuesdays, I have Portuguese class.

Aos sábados costumo jogar bilhar com o Paulo.
On Saturdays, I usually play pool with Paulo.

Notice “a” contracting with the articles:

a + as terças-feiras = às terças-feiras
a + os sábados = aos sábados

Em – One-off Events

We use “em” to refer to one-off events when mentioning days of the week:

Na terça-feira tenho aula de Português.
This Tuesday I have a Portuguese class.

No sábado vou jogar bilhar com o Paulo.
This Saturday, I’m going to play pool with Paulo.

We also use “em” when mentioning dates, holidays, months, or seasons:

No dia 15 de março tenho uma consulta no dermatologista.
I have a dermatologist’s appointment on March 15th.

Vou à Nicarágua no Natal.
I’m going to Nicaragua for Christmas.

A Rita vem a Portugal em fevereiro.
Rita is coming to Portugal in February.

No Verão a Ana está a planear ir passar uma semana ao Algarve.
This summer Ana is planning to spend a week in the Algarve.

Notice that in the examples above, apart from when we are directly referring to months, “em” contracts with the articles:

em + a terças-feira = na terça-feira
em + o dia 15 = no dia 15

Finally, for the most part we can replace “em” with the demonstratives este(s)/esta(s):

Na terça-feira tenho aula de Português.
=
Esta terça-feira tenho aula de Português.

Vou à Nicarágua no Natal.
=
Vou à Nicarágua este Natal.

Mark complete Completed

Real European Portuguese is harder than the textbook

If you can read Portuguese but real speech is still hard to follow, Portuguesepedia is built for that gap. A deep library of real EP audio, organized by level and topic, with AI-powered practice built in.

start free

No card required.

What learners say

I love the mix of formats. The listening pieces, short reads, exercises, and idioms cover different angles, so I don't get stuck doing the same thing. It keeps me coming back.

~ Olivia ~

It doesn’t feel like studying in the boring sense. The tone is light, but the practice is solid, and I’ve noticed I can put sentences together more easily.

~ Giulia ~

Everything feels well put together. I'll listen to something at my level, check a quick explanation when I'm confused, and then do a practice exercise. Everything I need is in one place and easy to find.

~ Liam ~

Portuguese used to feel messy, like I was putting in effort but not getting results. With Portuguesepedia, I can focus on what I actually need, and I’ve started noticing real improvement week by week.

~ Ebba ~

Something clicked after a few weeks. Real Portuguese started making more sense — not just on paper, but when I'm actually listening. I hadn't felt that kind of progress before.

~ Maria ~

I’d been trying to learn Portuguese for years, but I never felt confident using it. Textbooks were too much, and speaking classes made me freeze. With Portuguesepedia, things finally started to make sense.

~ Emely ~

Just added