Immediately after (по + prepositional)

In formal settings—such as legal documents, administrative instructions, or travel announcements—you will frequently encounter a special construction to mean "upon" or "immediately after."

In Russian, this is expressed using the preposition по paired with a noun in the Prepositional case.

upon / after (formal, e.g., upon arrival)
по

The Grammar of "Upon"

Most formal actions in Russian are expressed as neuter nouns ending in -ие (like возвращение — the return, or завершение — the completion).

When declining nouns that end in -ие into the Prepositional case, the ending changes to -ии. However, standard masculine nouns (like приезд — the arrival) simply take the regular Prepositional ending.

NominativePrepositional (with по)Meaning
возвращениепо возвращенииupon return
завершениепо завершенииupon completion
приездпо приездеupon arrival

Let's see this applied to immediate consequences, often paired with action verbs like приступить (to proceed).

Upon completion of the project, the team will receive a bonus.
По завершении проекта команда получит премию.

Administrative Procedures

This structure heavily features in bureaucracy and business. You will see it used to describe the sequence of official steps involving the signing (подписание), review (рассмотрение), or approval (утверждение) of documents.

Upon consideration of your application, we will immediately make a decision.
По рассмотрении вашей заявки мы немедленно примем решение.

It is also the standard way to talk about time limits and deadlines, using words like истечение (expiration).

Upon expiration of the term, you will have to buy a new ticket.
По истечении срока вам придётся купить новый билет.

Arrivals

Travel and hospitality rely on this grammar to instruct guests on what to do when they get to their destination. Notice how both прибытие (ends in -ие) and приезд (ends in a consonant) mean "arrival," but their Prepositional endings follow their respective declension rules.