Ég set sundfötin í töskuna áður en við förum á ströndina.

Sundfötin means the swimwear / the swimsuit, while sundföt means swimwear / swimsuit in a more indefinite sense.

The ending -in is the suffixed definite article in Icelandic. Instead of using a separate word like English the, Icelandic often attaches it to the noun.

So:

• sundföt = swimwear / a swimsuit
• sundfötin = the swimwear / the swimsuit

A useful thing to notice is that sundföt is grammatically plural in Icelandic, even when English might use a singular expression like a swimsuit.

Some items of clothing are commonly treated as plural nouns in Icelandic, much like English pants, shorts, or glasses.

So sundföt is literally something like swimming clothes. Even if English translation gives swimsuit, Icelandic grammar treats the word as plural.

That is why you see:

• sundföt
• sundfötin

rather than a singular form in this sentence.

Set is the present tense of að setja, which often means to put, to place, or to set.

In this sentence, Ég set sundfötin í töskuna means:

• I put the swimwear into the bag
• or more naturally, I’m putting the swimsuit in the bag

It is a very common verb for physically placing something somewhere.

This is about case after prepositions.

The preposition í can take either:

• accusative when something is moving into a place
• dative when something is in a place already

Here, the swimwear is being moved into the bag, so Icelandic uses the accusative:

• í töskuna = into the bag

Compare:

• Ég set sundfötin í töskuna. = I put the swimwear into the bag.
• Sundfötin eru í töskunni. = The swimwear is in the bag.

So:

• töskuna = accusative, movement into
• töskunni = dative, location inside

This is the same kind of pattern as í töskuna.

The preposition á can also take different cases depending on meaning:

• accusative for movement onto/to
• dative for location on/at

In this sentence, við förum á ströndina means we go to the beach, so there is movement toward the beach. That is why Icelandic uses the accusative:

• á ströndina = to the beach

Compare:

• Við förum á ströndina. = We go to the beach.
• Við erum á ströndinni. = We are at the beach.

Yes, áður en is a very common way to say before when it introduces a whole clause.

In this sentence:

• áður en við förum á ströndina
• before we go to the beach

Think of it as:

• áður = earlier / before
• en = than / before introducing the clause here

You use áður en when what follows has its own subject and verb:

• áður en við förum = before we go
• áður en hún kemur = before she comes

If there is no full clause after it, Icelandic may use other structures instead.

Because áður en við förum á ströndina is a subordinate clause, and Icelandic usually does not use the main-clause verb-second pattern inside such clauses.

So in a main clause you might get:

• Við förum á ströndina. = We go to the beach.

But after áður en, the normal order is:

• áður en við förum...

with the subject (við) before the verb (förum).

That is very normal Icelandic clause structure.

Förum is the 1st person plural present form of að fara (to go).

The verb fara changes stem in the present tense:

• ég fer = I go
• þú ferð = you go
• við förum = we go

So við förum simply means we go.

This is one of those very common Icelandic verbs whose forms need to be memorized rather than built mechanically from the infinitive.

It is the direct object of set, so logically it is in the accusative.

However, with sundfötin, the form looks the same as the nominative in this case, so you do not see a visible difference here.

That is common in Icelandic: sometimes the grammar says a noun is accusative, but the form happens to be identical to another case.

So functionally:

• Ég = subject
• set = verb
• sundfötin = direct object

Because Icelandic usually expresses the by attaching it to the end of the noun.

That is why you get forms like:

• taska = bag
• taskan = the bag
• töskuna = the bag, in accusative

and:

• strönd = beach
• ströndin = the beach
• ströndina = the beach, in accusative

This is called the suffixed definite article.

English uses a separate word (the), but Icelandic often builds that meaning into the noun itself.

Because Icelandic nouns change form for case, and the definite article changes with them.

For example:

• taska = bag
• töskuna = the bag, accusative singular

and:

• strönd = beach
• ströndina = the beach, accusative singular

So the full form reflects both:

1. the noun’s grammatical case
2. the fact that it is definite

This is why Icelandic nouns can look quite different from their dictionary form.

You could say til strandarinnar, but it would not mean exactly the same thing.

• á ströndina = to the beach
• til strandarinnar = toward/to the beach, with a slightly different construction

In everyday Icelandic, fara á ströndina is the natural expression for go to the beach.

So in this sentence, á ströndina is the most idiomatic choice.

It can mean either, depending on context.

The Icelandic present tense often covers both:

• a general/habitual action
• an action happening now
• even sometimes a near-future idea

So Ég set sundfötin í töskuna áður en við förum á ströndina could be understood as:

• I put the swimwear in the bag before we go to the beach
• I’m putting the swimwear in the bag before we go to the beach

Context tells you which feels more natural.

Then you would use the dative after í instead of the accusative.

For example:

• Sundfötin eru í töskunni. = The swimwear is in the bag.

That contrasts with:

• Ég set sundfötin í töskuna. = I put the swimwear into the bag.

So this sentence is specifically about movement into the bag, not just being inside the bag.

This one sentence shows several very common Icelandic patterns:

• Present tense verb: Ég set
• Definite noun with suffixed article: sundfötin
• Preposition + accusative for movement: í töskuna
• Subordinating expression: áður en
• Plural present of an irregular verb: við förum
• Another preposition + accusative for movement: á ströndina

So it is a very useful sentence because it combines everyday vocabulary with some core Icelandic grammar.