Šesnaestog srpnja idemo na more.

Because in Croatian, dates are usually expressed with an ordinal number in the genitive case.

So šesnaestog srpnja literally means something like of the sixteenth of July, with an implied noun such as dana (day):

• šesnaesti = the sixteenth (basic dictionary form)
• šesnaestog = genitive form, used in dates

This is one of the most important date patterns to learn:

• prvog siječnja
• petog svibnja
• desetog lipnja
• šesnaestog srpnja

Srpnja is also in the genitive case.

In Croatian dates, both the ordinal number and the month normally appear in the genitive:

• šesnaestog srpnja = on the sixteenth of July

Compare:

• srpanj = July (dictionary form, nominative)
• srpnja = genitive form

So the pattern is:

ordinal number (genitive) + month (genitive)

Yes, you can think of an implied word like dana (day).

So šesnaestog srpnja can be understood as shortened from something like:

• šesnaestog dana srpnja

In normal modern Croatian, you usually do not say the extra word. The shorter version is standard and natural.

Croatian usually does not need a preposition here.

So English:

• on the sixteenth of July

Croatian:

• šesnaestog srpnja

That is the normal way to say a date in a sentence.

Idemo is the 1st person plural present tense of ići (to go).

It means:

• we go
• and in this kind of sentence, very often we are going

So:

• idem = I go
• ideš = you go
• ide = he/she/it goes
• idemo = we go
• idete = you all go
• idu = they go

Because Croatian often uses the present tense for a planned future action, especially when there is a clear time expression.

Since the sentence already says šesnaestog srpnja (on the sixteenth of July), it is clear that the action is in the future.

So idemo na more here naturally means:

• we’re going to the seaside
• or we’re going to the sea
• on that future date

This is similar to English We’re going to the seaside on July 16th.

Yes. You could also say:

• Šesnaestog srpnja ići ćemo na more.

That is also correct and clearly future.

But idemo na more sounds very natural for a planned event, especially in everyday speech. In many situations, Croatian prefers this present-for-future usage when the time is already given.

This is a very common question.

In Croatian:

• ići na more = to go to the seaside / go on a seaside vacation
• ići u more = to go into the sea

So the difference is important:

• Idemo na more. = We’re going to the coast / seaside.
• Idemo u more. = We’re going into the water.

With na more, Croatian uses an idiomatic expression meaning a trip or holiday at the sea.

Literally, more means sea.

But in the expression ići na more, it often means going to the seaside / coast, especially for a holiday.

So although the literal word is sea, the natural English translation is often:

• go to the seaside
• go to the coast
• go to the sea
  depending on context

Here more is in the accusative case.

The noun more is a neuter noun, and its nominative and accusative singular forms are the same:

• nominative: more
• accusative: more

After na, when there is movement toward a destination, Croatian uses the accusative:

• Idemo na more. = We are going to the seaside.

Compare that with location:

• Na moru smo. = We are at the seaside / by the sea.

So:

• na more = motion toward
• na moru = location

In Croatian, names of months are normally written with a lowercase letter, not a capital letter.

So:

• srpanj
• kolovoz
• rujan

This is different from English, where July must be capitalized.

So srpnja with a lowercase s is correct.

Yes, very commonly.

You can write:

• 16. srpnja idemo na more.

The period after 16 is important, because in Croatian it shows an ordinal number.

So:

• 16. = sixteenth
• not just sixteen

This is often more common in writing than spelling the whole number out.

Yes, Croatian word order is fairly flexible.

This sentence:

• Šesnaestog srpnja idemo na more.

could also be:

• Idemo na more šesnaestog srpnja.

Both are correct.

The version with the date first sounds like:

• setting the time frame first
• On July 16th, we’re going to the seaside

The version with idemo na more first may sound a bit more like the main news is the trip itself.

A rough pronunciation guide is:

• Šesnaestog ≈ shes-NAES-tog
• srpnja ≈ SERP-nya or SRP-nya
• idemo ≈ ee-DEH-mo
• na more ≈ na MO-reh

A few useful sound notes:

• š sounds like sh in ship
• j sounds like y in yes
• nj sounds like the ny in canyon

So srpnja ends with that nya sound.

Yes. Croatian month names are native Slavic names, not international forms like July, August, and so on.

So:

• srpanj = July

This is completely normal in Croatian. Learners often notice that Croatian month names look very different from the English ones.

Probably these three things:

1. Dates use the genitive

   • šesnaestog srpnja

2. Present tense can express a planned future

   • idemo

3. ići na more is an idiomatic expression

   • go to the seaside / coast
   • not literally go onto the sea

If you remember those three points, you understand most of what makes this sentence work.