Na pristaništu već čeka mali brod koji ide prema luci.

Because na is expressing location here, so it takes the locative case.

The base noun is pristanište, a neuter noun. Its locative singular form is pristaništu.

So:

• pristanište = dock, landing place, pier
• na pristaništu = at the dock / on the pier / at the landing place

This is mostly a matter of normal Croatian usage.

With places like pristanište, Croatian typically uses na, not u, because the place is understood more like a surface, platform, or open arrival/departure point.

So:

• na pristaništu = the natural, idiomatic choice
• u pristaništu would sound odd or much less natural in this context

English learners often want to translate in and at very directly, but Croatian prepositions do not always match English one-to-one.

Već usually means already.

In this sentence it gives the sense that the small boat is already waiting or is there by now.

It often adds a feeling like:

• sooner than expected
• by this time
• now already in place

It can mean either, depending on context.

Croatian does not have a separate obligatory present continuous form like English is waiting. The plain present tense čeka can cover both:

• waits
• is waiting

In this sentence, the natural English meaning is usually is waiting.

Croatian word order is much more flexible than English word order.

Both are possible, but they put the focus in slightly different places.

In this sentence:

• Na pristaništu sets the scene first
• već čeka tells you what is happening
• mali brod introduces the thing that is waiting

So the sentence sounds natural and a bit more descriptive, almost like a narrative line.

If you said Mali brod već čeka na pristaništu, that would also be correct, but it would start with the subject rather than the location.

Because mali is the adjective small, and it must agree with brod in gender, number, and case.

Here:

• brod is masculine singular
• it is the subject
• so it is in the nominative singular

That is why the adjective is also in the masculine nominative singular form:

• mali brod = small boat

Koji is a relative pronoun. Here it means which, that, or sometimes who in other contexts.

It introduces the relative clause:

• koji ide prema luci = which is going toward the harbor

It refers back to brod.

So the structure is:

• mali brod = the small boat
• koji ide prema luci = that is going toward the harbor

Because it has to agree with the noun it refers to, and it also has to fit its role inside the relative clause.

It refers to brod, which is:

• masculine
• singular

And inside the clause koji ide prema luci, it is the subject of ide.

So the correct form is koji:

• masculine
• singular
• nominative

Ide is from the verb ići, which means to go.

This is the 3rd person singular present form:

• ići = to go
• ide = he/she/it goes, is going

Since brod is singular, the verb is singular too:

• brod ide = the boat goes / is going

Because the preposition prema takes the dative case.

The noun is:

• luka = harbor, port

Its dative singular form is:

• luci

So:

• prema luci = toward the harbor / toward the port

You may also notice the consonant change:

• k becomes c before i
• luka → luci

They are related, but not identical.

• pristanište is more like a landing place, dock, pier, or quay
• luka is more like a harbor or port

So in this sentence, the boat is waiting at the dock / landing place and is going toward the harbor.

Depending on context, English translations may overlap, but Croatian keeps these as distinct words.

Because Croatian does not have articles like English.

So mali brod can mean:

• a small boat
• the small boat

The exact meaning depends on context.

Croatian usually shows definiteness through:

• context
• word order
• adjectives
• shared knowledge between speaker and listener

So learners should not expect a separate word for the or a.