Ved ankomst til Odense ringer jeg til min søster med det samme.

Because ved ankomst til Odense is a compact, noun-based way of saying upon arrival in Odense or when I arrive in Odense.

A native English speaker often expects a full clause like:

• Når jeg ankommer til Odense ... = When I arrive in Odense ...

But Danish also often uses a preposition + noun structure:

• ved ankomst = upon arrival / on arrival

This version sounds a bit more formal, written, or concise than a full clause with når.

So:

• Ved ankomst til Odense ringer jeg ...
• Når jeg ankommer til Odense, ringer jeg ...

Both are natural, but the first is more compressed in style.

Here ved means something like upon, on, or at the time of.

English learners often first learn ved as:

• by
• near
• at

But in this sentence, it is used in a time-related expression:

• ved ankomst = upon arrival / on arrival

So this is not really the physical by meaning. It is part of a set phrase that introduces the time when something happens.

Because in Danish, nouns in fixed expressions often appear without an article.

So:

• ved ankomst literally looks like at arrival
• but naturally means upon arrival

This is similar to English expressions like:

• on arrival
• after dinner
• before departure

You do not need en here, because the phrase is functioning as a general event/time expression, not as one arrival being counted as an object.

Because ankomst often connects with til to show the destination.

Examples:

• ankomst til Odense = arrival in/to Odense
• ankomst til lufthavnen = arrival at the airport

Even though English often says arrival in Odense, Danish commonly uses til with ankomst to mark where the arrival is.

Also, Odense is a city name, so there is no article before it.

This is because Danish is a V2 language in main clauses. That means the finite verb normally comes in the second position.

The sentence begins with an adverbial phrase:

• Ved ankomst til Odense

Since that first slot is already occupied, the verb must come next:

• Ved ankomst til Odense ringer jeg ...

Not:

• Ved ankomst til Odense jeg ringer ... ❌

Compare:

• Jeg ringer til min søster med det samme.
• Ved ankomst til Odense ringer jeg til min søster med det samme.

In both cases, the verb ringer is in second position.

Because when ringe means to phone/call someone, Danish usually uses til before the person.

So:

• ringe til nogen = to call someone

Examples:

• Jeg ringer til min mor.
• Han ringede til lægen.

This is different from English, where we usually say call someone without a preposition.

So a direct translation like I ring my sister is not the normal Danish pattern here. The normal pattern is:

• Jeg ringer til min søster.

Yes. Ringe can refer to:

1. calling someone on the phone
2. something making a ringing sound

In this sentence, because of til min søster, it clearly means to call/phone.

Compare:

• Jeg ringer til min søster. = I call my sister.
• Telefonen ringer. = The phone is ringing.

So the surrounding words tell you which meaning is intended.

In Danish, a possessive like min, din, hans, vores, etc. normally goes directly before the noun, and then the noun is usually indefinite in form:

• min søster = my sister
• min bil = my car

So you do not say:

• den min søster ❌
• min søsteren ❌

There is also another possible Danish pattern:

• søsteren min

That can be used in some contexts, often with a slightly more spoken, contrastive, or emphatic feel. But the most neutral form here is:

• min søster

Med det samme is a fixed expression meaning:

• immediately
• right away
• at once

It is not meant to be translated word-for-word as with the same in normal English.

So in this sentence it means that the speaker will call the sister without delay after arriving.

Some near equivalents are:

• straks
• med det samme
• øjeblikkeligt (more formal/stronger)

Yes, it can move, although the end position is very natural.

The original sentence:

• Ved ankomst til Odense ringer jeg til min søster med det samme.

You could also say:

• Ved ankomst til Odense ringer jeg med det samme til min søster.

That is possible, but it may sound slightly different in rhythm or emphasis.

If you front med det samme, then V2 word order still applies:

• Med det samme ringer jeg til min søster ved ankomst til Odense.

That is grammatical, but it sounds less natural for this exact context.

So the clause-final position is a very normal place for it.

Yes, it sounds somewhat more formal, written, or compact than everyday spoken Danish.

A more conversational version would often be:

• Når jeg kommer til Odense, ringer jeg til min søster med det samme.
• Når jeg ankommer til Odense, ringer jeg til min søster med det samme.

So if you are speaking casually, many Danes would probably choose a når-clause rather than ved ankomst.

Not in this exact phrase.

With ankomst, Danish normally uses til for the destination:

• ankomst til Odense

If you used i Odense, that would more naturally belong with a different construction, for example:

• Når jeg er i Odense ... = When I am in Odense ...
• Når jeg kommer til Odense ... = When I come to Odense ...

So with ankomst, til is the expected choice.

A few points may help:

• Ved is usually pronounced roughly like vel without a clear l at the end, depending on accent and reduction.
• ankomst has stress on the second syllable: an-KOMST
• Odense is commonly pronounced approximately OH-thən-sə or OH-dən-sə, depending on speaker and accent, not like it is spelled letter-by-letter.
• ringer is pronounced with the Danish r, which may be difficult for English speakers.
• søster contains ø, a vowel English does not really have. It is not the same as o or u.
• det in med det samme is often pronounced very weakly in connected speech.

The sentence will often sound more connected and reduced in natural speech than a learner expects from the spelling.

Usually ved ankomst is better here.

• ved ankomst means upon arrival / at arrival
• efter ankomst means after arrival

That may sound similar, but efter ankomst suggests a point after the arrival event, while ved ankomst suggests something happening as soon as one arrives or on arriving.

Since the sentence already includes med det samme, ved ankomst fits the idea especially well.