Увечері берег моря тихий.

Увечері is an adverb meaning in the evening.

In context, it can sometimes also be understood as this evening / tonight, but the basic meaning is simply in the evening.

So in this sentence, it sets the time:

• Увечері = in the evening

Because увечері is just a short adverbial time expression at the beginning of the sentence, and Ukrainian normally does not separate that with a comma.

So this is standard:

• Увечері берег моря тихий.

A comma would usually appear only if there were some special pause, emphasis, or a more complex structure.

In Ukrainian, the verb to be in the present tense is usually omitted.

So:

• берег моря тихий

literally looks like:

• shore of-the-sea quiet

but it means:

• the seashore is quiet

This is completely normal in Ukrainian. If the sentence were in the past or future, you would normally see a form of бути:

• Берег моря був тихий. = The seashore was quiet.
• Берег моря буде тихий. = The seashore will be quiet.

Because моря is the genitive singular form of море (sea).

Here it is used after another noun:

• берег моря = shore of the sea

This is a very common pattern in Ukrainian:

• центр міста = city center, literally center of the city
• дах будинку = roof of the house

So:

• море = sea
• моря = of the sea

Берег is in the nominative singular.

It is the main noun of the sentence, the thing being described:

• берег моря = the shore of the sea
• тихий = quiet

So берег is the subject, and тихий agrees with it.

Because тихий must agree with берег in gender, number, and case.

Берег is:

• masculine
• singular
• nominative

So the adjective also has to be:

• masculine singular nominative → тихий

Compare:

• берег тихий = the shore is quiet
• море тихе = the sea is quiet
• ніч тиха = the night is quiet
• хвилі тихі = the waves are quiet/calm

It can cover several related ideas, depending on context.

For тихий, common English translations include:

• quiet
• calm
• still

With берег моря, it suggests that the shore is peaceful, not noisy, perhaps calm and still.

So quiet is a very natural translation here, but calm may also fit the mood.

Ukrainian has no articles like English a/an/the.

That means the noun itself does not show whether it is:

• a shore
• the shore
• the seashore

You figure that out from context.

In an isolated sentence like this, English will often use the:

• In the evening, the seashore is quiet.

But in another context, a shore might also be possible.

Yes. Ukrainian word order is fairly flexible, and changing it often changes the emphasis, not the basic meaning.

This version:

• Увечері берег моря тихий.

sounds natural and neutral, with time given first.

Other possible orders:

• Берег моря тихий увечері.
  More emphasis on the shore first.
• Тихий увечері берег моря.
  More poetic or marked.

So the sentence you have is a normal, clear way to say it.

Not exactly.

• берег моря = the shore of the sea, the edge by the water
• узбережжя = the coast / coastline / coastal area

So берег моря is more literally the seashore or the shore, while узбережжя can be broader.

In many contexts they may translate similarly, but they are not always interchangeable.

Yes, it can.

Without extra context, увечері may refer to:

• a specific evening: this evening / that evening
• evening time in general: in the evening
• sometimes a habitual sense, depending on context

For example:

• Увечері тут тихо. = It is quiet here in the evening / in the evenings.

So context tells you whether it is a one-time situation or a general truth.