Chúng tôi bơi ở biển.

Chúng tôi means we.

• tôi = I
• chúng tôi = we / us

The word chúng makes the pronoun plural, so chúng tôi refers to more than one person.

A very important point: chúng tôi usually means we, but not you. It excludes the person being spoken to.

So if I say Chúng tôi bơi ở biển, I mean We swim at the beach / in the sea, and I am not including the listener in we.

This is one of the most common questions for English speakers because English has only one word, we, but Vietnamese makes an important distinction:

• chúng tôi = we, excluding the listener
• chúng ta = we, including the listener

So:

• Chúng tôi bơi ở biển. = We swim at the beach/in the sea — but not you
• Chúng ta bơi ở biển. = We swim at the beach/in the sea — including you

English does not normally mark this difference, but Vietnamese often does.

Vietnamese verbs do not change form for tense the way English verbs do.

The verb bơi stays bơi whether the action is present, past, or future. Time is usually understood from:

• context
• time words
• extra markers like đã, đang, sẽ

Examples:

• Chúng tôi bơi ở biển. = We swim / We are swimming / We swam, depending on context
• Chúng tôi đang bơi ở biển. = We are swimming at the beach / in the sea
• Chúng tôi đã bơi ở biển. = We swam at the beach / in the sea
• Chúng tôi sẽ bơi ở biển. = We will swim at the beach / in the sea

So the basic sentence is tenseless by itself.

bơi is a verb, and it means to swim.

In Chúng tôi bơi ở biển:

• Chúng tôi = subject
• bơi = verb
• ở biển = location phrase

So the sentence structure is very straightforward: Subject + Verb + Place.

Vietnamese often uses bare verbs without extra words that English sometimes needs. So bơi can cover ideas like:

• swim
• are swimming
• go swimming

depending on context.

Ở is a very common preposition/location marker in Vietnamese. It often means:

• at
• in
• on
• sometimes to be located at

In this sentence, ở biển gives the location of the action:

• bơi ở biển = swim at the beach / by the sea / in the sea, depending on context

Vietnamese prepositions do not always match English ones one-to-one. English distinguishes at the beach and in the sea, but Vietnamese can express the general location more flexibly with ở.

It can depend on context.

Literally, biển means sea or beach/coast depending on usage, so ở biển can suggest being at the seaside or at the sea.

With the verb bơi (to swim), the overall meaning is usually understood naturally as something like:

• swim at the beach
• swim in the sea
• go swimming by the sea

If you want to be more specific, Vietnamese can do that too. For example:

• bơi ngoài biển = swim out in the sea
• bơi dưới nước = swim in the water

But bơi ở biển is understandable as a general location expression.

Vietnamese does not use articles the same way English does.

English uses:

• a
• an
• the

Vietnamese normally does not have direct equivalents that must appear before nouns in ordinary sentences.

So:

• biển can mean sea, the sea, or even the beach/coast, depending on context

This is very normal in Vietnamese. Learners often want to insert something where English would use the, but Vietnamese usually just uses the noun by itself.

Yes. This sentence follows a very common Vietnamese pattern:

Subject + Verb + Location

So:

• Chúng tôi = subject
• bơi = verb
• ở biển = place

This is similar to English:

• We swim at the beach.

Because the word order is fairly close to English here, this sentence is easier for beginners than many other Vietnamese structures.

Sometimes yes, if the subject is already clear from context.

Vietnamese often drops subjects when they are obvious. For example, in a conversation, someone might simply say:

• Bơi ở biển.

But on its own, that can sound incomplete in English translation because English usually requires a subject. Vietnamese is more flexible.

In a textbook-style example, Chúng tôi bơi ở biển is complete and clear, so it is a good full sentence for learners.

It is a correct and understandable sentence, but Vietnamese also has other very common ways to express similar ideas.

For example:

• Chúng tôi đi bơi ở biển. = We go swimming at the beach / in the sea.
• Chúng tôi tắm biển. = We swim/bathe in the sea; we go sea-bathing.

A few notes:

• bơi focuses directly on the act of swimming.
• đi bơi often sounds like go swimming.
• tắm biển is a very common natural expression for enjoying the sea water at the beach, even if the activity is not serious lap-swimming.

So your sentence is fine, but there are other natural alternatives depending on the exact situation.

A rough pronunciation guide is:

• Chúng tôi ≈ choong toy
• bơi ≈ something like buh-ee / boi with the correct Vietnamese vowel
• ở ≈ uh with the proper tone
• biển ≈ roughly bee-en with a gliding vowel and tone

A more careful learner note:

• Vietnamese is a tonal language, so the tones matter a lot.
• Even if the consonants and vowels are close, the wrong tone can make the word hard to understand.
• biển has a different tone from plain biên or biện, for example.

If you are studying pronunciation, it is best to listen to a native recording and copy the tones along with the vowels, rather than relying only on English-style approximations.