Learn Hardcore Portuguese (Portugal): Eu vou chegar cedo, mas os outros vão chegar tarde. - I am going to arrive early, but the others are going to arrive late.

In normal conversation, vou chegar is much more natural than chegarei in Portugal. They mean the same thing here; the difference is mainly style and register.

Can we drop eu and just say Vou chegar cedo, mas os outros vão chegar tarde?

Yes. Subject pronouns are often omitted in Portuguese because the verb ending usually shows who the subject is.

(Eu) vou chegar cedo… – both are correct.

Why include eu at all? Often to give emphasis or contrast:

Eu vou chegar cedo, mas os outros vão chegar tarde.
→ Highlights the contrast between me and the others.

So:

Vou chegar cedo, mas os outros vão chegar tarde. – perfectly natural.
Eu vou chegar cedo, mas os outros vão chegar tarde. – same meaning, with a bit more focus on “I”.

Do we ever need a preposition after chegar, like chegar a or chegar em?

Yes, when you say where you arrive, you normally need a preposition. In European Portuguese:

The standard is chegar a:
- Chegar a casa – to arrive home
- Chegar a Lisboa – to arrive in Lisbon

In this sentence, there is no place expressed, only a time (early/late), so you just use chegar:

Eu vou chegar cedo. – I’m going to arrive early.

If you add a place, you add the preposition:

Eu vou chegar cedo a casa. – I’m going to get home early.
Eu vou chegar cedo ao trabalho. – I’m going to arrive early at work.

Note: chegar em is much more Brazilian; in Portugal chegar a is the norm.

What exactly does os outros mean here, and why do we need the article os?

Os outros literally means “the others” – the other people in a group that is already known from context.

Eu vou chegar cedo, mas os outros vão chegar tarde.
→ I will arrive early, but the others (in our group) will arrive late.

The definite article os is normally required when you talk about a specific group:

os outros – the others (the rest of them)

If you say only outros as a subject, it usually sounds incomplete or too vague:

Outros vão chegar tarde. – Possible, but sounds like “some other people” in a very generic way, and needs a richer context.

In most normal contexts like this, you’d say os outros.

Are cedo and tarde adjectives or adverbs? Why don’t they change for gender or number?

In this sentence, cedo and tarde are adverbs of time (they modify chegar, telling us when you arrive).

chegar cedo – to arrive early
chegar tarde – to arrive late

Adverbs in Portuguese are generally invariable: they do not change for gender or number. That’s why you don’t get forms like:

❌ ceda, cedos, tardas, tardes (as adverbs – these don’t exist)

They stay the same:

Eu vou chegar cedo.
Eles vão chegar cedo.
Ela chega tarde.
Nós chegamos tarde.

Same form for all subjects.

Could we say os outros chegam tarde with the present tense instead of os outros vão chegar tarde?

Yes, in the right context you can use the present to talk about the future, like in English:

Amanhã, os outros chegam tarde. – Tomorrow, the others arrive late.

Differences:

vão chegar tarde – clearly future; often used for plans, decisions, predictions.
chegam tarde – sounds more like a fixed schedule or a regular habit, or like a statement of what normally happens.

In many real situations, both can work. For a one-off future plan, vão chegar tarde is the safest, most neutral choice.

Can cedo or tarde go in a different position in the sentence?

Yes, but not just anywhere. The most natural positions are:

After the verb phrase (most common and neutral):
- Eu vou chegar cedo.
- Os outros vão chegar tarde.
Sometimes before the verb for emphasis (especially in writing):
- Cedo vou chegar, mas os outros vão chegar tarde. – sounds a bit literary/emphatic.

Constructions like:

❌ Eu cedo vou chegar

are technically possible but sound unnatural or strongly marked in most everyday speech. For learners, keep cedo/tarde after the verb:

vou chegar cedo, vão chegar tarde.

What is the conjugation of ir in this future construction like vou chegar?

You use the present tense of ir + infinitive of the main verb. For ir in European Portuguese (main everyday forms):

eu vou – I go / I’m going to
tu vais – you go / you’re going to (informal singular)
ele / ela / você vai – he/she/you go(es) / are going to
nós vamos – we go / we’re going to
vocês / eles / elas vão – you (pl.) / they go / are going to

Then add the infinitive chegar:

Eu vou chegar cedo.
Tu vais chegar cedo.
Eles vão chegar tarde.

This pattern works for almost all verbs:

vou comer, vamos sair, vão trabalhar, etc.

Why isn’t there an a between vão and chegar, like vão a chegar?

When ir is used as an auxiliary to form the future (ir + infinitive), you do not use any preposition:

vão chegar – they are going to arrive

Adding a would change the structure:

vão a chegar – this is not the standard future form and sounds wrong here.

Compare:

Vou comprar pão. – I’m going to buy bread. (future)
Vou ao supermercado comprar pão. – I’m going to the supermarket to buy bread.

Here the a (in ao) belongs to ir + place, not to the infinitive verb. With ir + infinitive (future), it’s just:

ir + infinitive: vou chegar, vão chegar, vamos sair, etc.

Is mas the only way to say “but” here? Could we use porém or só que?

Other words can mean “but”, but mas is the most neutral and common in speech:

Eu vou chegar cedo, mas os outros vão chegar tarde.

Alternatives:

porém – more formal/literary; sounds heavier in everyday speech:
- Eu vou chegar cedo; porém, os outros vão chegar tarde. (more like written style)
só que – very colloquial, often used in spoken Portuguese with a nuance like “except that” / “it’s just that”:
- Eu vou chegar cedo, só que os outros vão chegar tarde.

For learners, mas is the default, safest choice for “but”.