Дата окончания срока действия зависит от даты выдачи.

This is a very common Russian pattern: a main noun followed by one or more nouns in the genitive case to narrow the meaning.

Here, the structure is:

• дата = date
• окончания = of ending / of expiration
• срока действия = of the period of validity

So literally, it is something like:

• date of the ending of the validity period

In more natural English, that becomes expiration date or end date of validity.

Russian often builds these long noun chains where English might prefer a shorter compound like expiration date.

Окончания is in the genitive singular.

Its dictionary form is окончание. After дата, Russian often uses the genitive to mean date of something:

• дата рождения = date of birth
• дата выдачи = date of issue
• дата окончания = date of expiration / end date

So окончания answers the question date of what? That is why it is genitive.

Because срок действия is a fixed expression meaning period of validity, term of validity, or validity period.

Breaking it down:

• срок = term, period, deadline
• действия = of functioning / of validity / of being in force

So:

• срок действия паспорта = the validity period of a passport
• срок действия договора = the term of a contract

In your sentence, окончания срока действия means the end of the validity period.

Not in this sentence.

The noun действие can mean action, but in official or legal language it also often means validity, effect, or being in force.

So in срок действия, it does not mean a physical action. It means something more like:

• the period during which something is valid
• the time during which something remains in effect

That is why срок действия is often translated as validity period.

Because the Russian verb зависеть requires the preposition от plus the genitive case.

So the pattern is:

• зависеть от + genitive = to depend on

Examples:

• Это зависит от погоды. = It depends on the weather.
• Всё зависит от тебя. = Everything depends on you.
• Дата зависит от даты выдачи. = The date depends on the date of issue.

So от даты выдачи is exactly what Russian grammar requires after зависит.

Because after от, Russian uses the genitive case.

The base forms are:

• дата → genitive даты
• выдача → genitive выдачи

So:

• от даты = from / on / depending on the date
• даты выдачи = date of issue

Together:

• от даты выдачи = on the date of issue / depending on the date of issue

Even though English uses on, Russian uses от because that is what зависеть requires.

Выдача is a noun meaning issuance, issue, giving out, or delivery, depending on context.

It comes from the verb выдавать / выдать:

• выдать документ = to issue a document
• дата выдачи = date of issue

This phrase is extremely common in documents:

• дата выдачи паспорта = passport issue date
• место выдачи = place of issue

So in your sentence, дата выдачи means the date when the document was issued.

The subject is the whole noun phrase:

• Дата окончания срока действия

The verb is:

• зависит = depends

So the sentence structure is:

• [Дата окончания срока действия] зависит [от даты выдачи].

Literally:

• [The expiration date] depends [on the issue date].

The verb is singular because the head noun дата is singular.

Because the grammatical subject is дата, which is singular.

Even though the subject contains several nouns, the main noun is still just one noun:

• дата = date

Everything after it just describes which date:

• дата окончания срока действия

So Russian agrees the verb with дата, not with all the nouns in the phrase.

That is why it is:

• дата ... зависит

and not a plural form.

Yes. In official language, you may also see phrases like:

• дата истечения срока действия
• срок действия истекает

Both are related to expiration.

A rough comparison:

• окончание = ending, end
• истечение = expiration, lapse, coming to an end

So:

• дата окончания срока действия = date of the end of the validity period
• дата истечения срока действия = date of expiration of the validity period

Both are natural in formal Russian, especially in documents.

Yes, it sounds quite formal and document-like.

Expressions such as:

• срок действия
• дата выдачи
• дата окончания

are very common in forms, contracts, certificates, visas, permits, and IDs.

A normal conversation might use something simpler depending on context, but in official writing this style is completely standard.

Because Russian often prefers noun + genitive structures where English prefers compact noun modifiers.

Compare:

• date of birth → дата рождения
• issue date → дата выдачи
• expiration date → дата окончания срока действия

English often compresses information into a noun used like an adjective. Russian usually keeps the relationship clearer through case endings.

So what feels long to an English speaker is often perfectly normal in Russian.

The neutral word order is:

• Дата окончания срока действия зависит от даты выдачи.

This is the most natural order in formal writing: subject first, then verb, then complement.

You could rearrange parts for emphasis, but in a document this standard order is best.

For example, moving от даты выдачи to the front would be possible in some contexts, but it would sound less neutral:

• От даты выдачи зависит дата окончания срока действия.

That version emphasizes the date of issue more strongly.

Both are grammatically correct. The original is simply the more standard phrasing for official text.