Hvenær opnar innritunin á flugvellinum?

Because Icelandic direct questions usually put the finite verb right after the question word. This is part of the usual verb-second pattern.

So:

• Hvenær = question word
• opnar = finite verb
• innritunin = subject

That is why Hvenær opnar innritunin? is the normal direct-question order.

The order Hvenær innritunin opnar would sound like part of a longer sentence, for example:

• Ég veit ekki hvenær innritunin opnar.
  = I do not know when the check-in opens.

So the same words can appear in a different order inside a subordinate clause.

Icelandic does not use do-support the way English does.

In English, we say:

• When does check-in open?

But in Icelandic, the main verb itself carries the tense, so opnar already means opens / does open. There is no extra helper word corresponding to English does here.

So a more literal breakdown is:

• Hvenær = when
• opnar = opens
• innritunin = the check-in

Opnar is the present tense, 3rd person singular form of the verb opna.

Base form:

• að opna = to open

Present tense:

• ég opna = I open
• þú opnar = you open
• hann / hún / það opnar = he / she / it opens

Here the subject is innritunin, which is grammatically singular, so opnar is the correct form.

Because Icelandic, like English, often uses the present tense for scheduled or expected future events.

So Hvenær opnar innritunin á flugvellinum? can naturally refer to a future schedule, just like English:

• When does check-in open at the airport?

This is especially common with timetables, opening hours, departures, arrivals, and similar planned events.

Because Icelandic usually adds the definite article to the end of the noun.

• innritun = check-in
• innritunin = the check-in

Here, -in is the definite ending for this feminine noun in the nominative singular.

So innritunin is not a different word altogether; it is innritun with the suffixed article.

Innritunin is in the nominative case because it is the subject of the sentence.

The thing doing the opening, grammatically speaking, is the check-in, so it appears in the nominative:

• innritunin opnar = the check-in opens

Even though English learners often focus on word order first, Icelandic also marks roles through case, and the subject here is nominative singular definite.

Here á means at / on, and because the phrase describes a location rather than movement, it takes the dative case.

So:

• á flugvellinum = at the airport

Important contrast:

• á
  • dative = location, being at/on somewhere
• á
  • accusative = movement onto/to something

In this sentence, check-in is opening at the airport, not moving to the airport, so the dative is used.

Because Icelandic nouns often change form quite a bit when they go into different cases and when the definite article is added.

The basic dictionary form is:

• flugvöllur = airport

In the dative singular, without the article, it becomes:

• flugvelli = at an airport

With the definite article added, it becomes:

• flugvellinum = at the airport

So two things are happening:

1. the noun changes for case
2. the definite article is added at the end

The vowel change from ö to e is part of the noun’s normal inflection pattern.

Because the sentence is talking about a specific check-in and a specific airport, or at least ones understood from context.

So:

• innritunin = the check-in
• flugvellinum = the airport

This is very natural in Icelandic when both speaker and listener know what is being referred to, for example a particular flight and the airport connected with it.

English sometimes sounds more general in similar situations, but Icelandic often makes the nouns definite when the reference is specific.

Usually, opnar is the most natural choice here.

• opnar = opens
• opnast = opens / gets opened, with a more middle or passive-like feel

In everyday Icelandic, scheduled things like offices, desks, services, and check-in commonly use opnar. It works much like English opens in:

• When does check-in open?

So for this sentence, Hvenær opnar innritunin á flugvellinum? is the straightforward and idiomatic version.