Ég set sólkremið á húðina áður en ég fer á ströndina.

Because setja is the infinitive, meaning to put or to apply, while set is the 1st person singular present tense form.

So:

• að setja = to put / to apply
• ég set = I put / I apply

In this sentence, the subject is ég (I), so the verb has to match that subject:

• Ég set sólkremið ... = I apply the sunscreen ...

This verb is very commonly used for applying something onto a surface, including cream, lotion, or sunscreen.

Sólkrem means sunscreen or sun cream.

The ending -ið is the definite article, attached to the noun. So:

• sólkrem = sunscreen
• sólkremið = the sunscreen

Icelandic usually adds the to the end of the noun instead of using a separate word like English does.

So the sentence literally says I put the sunscreen on the skin..., even though in natural English we often just say I put on sunscreen.

Because á can take different cases depending on the meaning.

Here, á means onto / on to, with a sense of movement or direction, so it takes the accusative:

• á húðina = onto the skin

If you were describing location, meaning on the skin in a static sense, you would often use the dative:

• á húðinni = on the skin

So this sentence uses á húðina because the sunscreen is being applied onto the skin.

Húð means skin.
Húðina means the skin.

The ending -ina shows two things at once:

• the noun is definite: the skin
• the noun is in the accusative singular

So:

• húð = skin
• húðin = the skin (nominative)
• húðina = the skin (accusative)

Because á here requires the accusative, you get á húðina.

That is a very natural question. Icelandic often uses the definite form with body-related nouns in places where English might prefer my, your, or sometimes no article at all.

So á húðina literally means onto the skin, but in context it naturally means something like:

• on my skin
• onto the skin

Icelandic does not always need a possessive like mína (my) when it is already obvious whose skin is meant.

A more explicit version with my is possible in some contexts, but á húðina sounds very natural here.

Áður en means before.

It introduces a whole clause:

• áður en ég fer á ströndina = before I go to the beach

This is different from using just a noun phrase. Compare:

• áður en ég fer = before I go
• áður en sumarið byrjar = before the summer begins

So áður en is a very common way to say before when a full clause follows.

Because áður en introduces a subordinate clause, and clauses need a finite verb.

So you say:

• áður en ég fer = before I go

Not:

• áður en ég að fara ✘

Here:

• fer is the present tense of fara (to go)
• ég fer = I go

In other words, áður en works like English before in before I go, not like before going.

Yes, but Icelandic often uses the present tense for things that are habitual, scheduled, or understood as future from context.

So:

• áður en ég fer á ströndina literally = before I go to the beach
• but in context it can mean before I go to the beach later or before I go to the beach in general

This is very similar to English, which also says:

• I put on sunscreen before I go to the beach

not necessarily

• before I will go to the beach

So the present tense is completely natural here.

This is the same movement-vs-location pattern as with á húðina.

• á ströndina = to the beach / onto the beach → movement, so accusative
• á ströndinni = at/on the beach → location, so dative

Since fara means to go, there is movement toward a destination:

• ég fer á ströndina = I go to the beach

But:

• ég er á ströndinni = I am at the beach

This is one of the most important case patterns in Icelandic.

The base noun is strönd = beach.

In this sentence, it appears as ströndina, which is:

• singular
• definite = the beach
• accusative

That form is used because á with motion takes the accusative:

• á ströndina = to the beach

So the ending reflects both the and the required case.

Yes, setja á sig sólkrem or setja sólkrem á húðina is very natural.

In this sentence, setja means to put/apply. With creams, lotions, makeup, and similar things, Icelandic often uses setja in a way that matches English put on or apply.

Very common patterns include:

• setja á sig sólkrem = put sunscreen on oneself
• setja krem á andlitið = put cream on the face

So this sentence sounds natural and idiomatic.

Yes, that would also be natural.

Compare:

• Ég set sólkremið á húðina = I put the sunscreen on the skin
• Ég set sólkrem á mig = I put sunscreen on myself

The second version is often more conversational and less anatomically specific. The first version focuses more on the surface receiving the sunscreen, while á mig focuses on the person.

Both are possible, but á mig is especially common in everyday speech.

In this sentence, the word order is quite close to English:

• Ég = subject
• set = verb
• sólkremið = object
• á húðina = prepositional phrase
• áður en ég fer á ströndina = time clause

So the structure is:

Subject + Verb + Object + Adverbial phrase + Subordinate clause

That said, Icelandic is a V2 language, which means the finite verb often stays in the second position in main clauses. If you move the time clause to the front, the verb position changes:

• Áður en ég fer á ströndina, set ég sólkremið á húðina.

Notice how set comes right after the fronted clause. That is a very Icelandic pattern.

It can be understood either way, depending on context, but by itself it most naturally sounds like a habitual or general statement:

• I put on sunscreen before I go to the beach.

The present tense in Icelandic often works like English present tense for routines and normal behavior.

If the speaker were describing a specific event happening right now or today, the same form could still work if the context made that clear. But without extra context, it sounds like a general routine.

A fairly literal translation would be:

• I put the sunscreen onto the skin before I go to the beach.

But more natural English would usually be:

• I put on sunscreen before I go to the beach.
• I apply sunscreen before going to the beach.

So when learning Icelandic, it helps to notice that the grammar may be more explicit than the most natural English version, especially with things like:

• the attached definite article
• body-part nouns like húðina
• directional use of á with the accusative