La valideco de la vizo finiĝas morgaŭ.

The subject is la valideco.

So the sentence is structured like this:

• La valideco = the validity
• de la vizo = of the visa
• finiĝas = ends / expires
• morgaŭ = tomorrow

A common mistake is to focus on la vizo as the main noun, but grammatically it is only part of the de phrase modifying valideco.

Valideco is built from:

• valida = valid
• -ec- = the quality or state of something
• -o = noun ending

So:

• valida = valid
• valideco = validity

This is a very common Esperanto word-building pattern. For example:

• bela = beautiful
• beleco = beauty

De often means of and is used to show a relationship between two nouns.

So la valideco de la vizo literally means the validity of the visa.

This is a very normal way to connect nouns in Esperanto. English often uses of or an apostrophe, and Esperanto commonly uses de.

Because both noun phrases are definite:

• la valideco = the validity
• la vizo = the visa

In Esperanto, if both nouns are definite, both can take la.
So de la vizo means of the visa, not just of a visa.

If you said valideco de vizo, that would sound more general, like validity of a visa or visa validity in general.

Finiĝas comes from finiĝi.

The important part here is -iĝ-, which often means to become or to undergo a change of state. So:

• fini = to finish, to bring to an end
• finiĝi = to end, to come to an end

So finiĝas means comes to an end, ends, or in this context expires.

That is why it fits well with valideco: the period of validity is ending.

Because finiĝas is intransitive: the validity itself is coming to an end.

By contrast, finas usually suggests that someone or something is finishing something else. For example:

• Mi finas la laboron. = I am finishing the work.

Here, nobody is actively finishing the validity; the validity period simply reaches its end. That makes finiĝas the natural choice.

This is similar to English sentences like The visa expires tomorrow.

Even though morgaŭ refers to the future, the present tense can be used for something scheduled, certain, or viewed as a fixed fact. So finiĝas morgaŭ is understandable and natural.

That said, finiĝos morgaŭ is also perfectly natural and is more explicitly future. If you want the clearest textbook-style future, use finiĝos.

Because there is no direct object in this sentence.

• la valideco is the subject
• de la vizo is a prepositional phrase
• morgaŭ is an adverb of time

The accusative -n is mainly used for direct objects and some expressions of direction or time. None of those apply here.

Because morgaŭ is already an adverb meaning tomorrow.

Esperanto time adverbs often stand alone:

• hodiaŭ = today
• hieraŭ = yesterday
• morgaŭ = tomorrow

So just as in English you say tomorrow, in Esperanto you can simply say morgaŭ.

Yes, and many people would say that in everyday speech.

It means roughly The visa expires tomorrow, which is very natural in English too. But it is slightly less precise than La valideco de la vizo finiĝas morgaŭ, because strictly speaking it is the visa’s validity that ends, not the physical visa itself.

So:

• La vizo finiĝas morgaŭ. = everyday, shorter
• La valideco de la vizo finiĝas morgaŭ. = more precise

Yes. Esperanto word order is fairly flexible, especially when prepositions make relationships clear.

For example, you could also say:

• Morgaŭ finiĝas la valideco de la vizo.

That version puts more emphasis on morgaŭ.
The original order is neutral and straightforward, so it is a very good default.