Güneş kremi sürmeden kumsala gitmemelisin.

Yes, sürmek has several meanings. In this sentence, it means to apply / spread on something, especially with things like:

• güneş kremi sürmek = to apply sunscreen
• krem sürmek = to put on cream
• merhem sürmek = to apply ointment

So here it does not mean to drive.

sürmeden comes from:

• sür- = apply
• -meden / -madan = without doing

So:

• sürmeden = without applying

This suffix is very common in Turkish:

• yemeden = without eating
• gitmeden = without going
• bakmadan = without looking

So Güneş kremi sürmeden... means without applying sunscreen...

Here güneş kremi is being used in a more general, non-specific way: sunscreen as a type of thing, not a particular bottle or specific sunscreen.

In Turkish, a direct object is often:

• without accusative when it is non-specific/general
• with accusative when it is specific

So:

• güneş kremi sürmek = to apply sunscreen
• güneş kremini sürmek = to apply the sunscreen / a specific sunscreen

In this sentence, the general meaning is enough, so güneş kremi sounds natural.

Because güneş kremi is an izafet construction, often called a noun compound in Turkish.

It is:

• güneş = sun
• kremi = its cream / cream of the sun → sun cream / sunscreen

In these compounds, the second noun usually takes a third-person possessive ending:

• elma suyu = apple juice
• diş fırçası = toothbrush
• güneş kremi = sun cream / sunscreen

So the -i in kremi belongs to the compound structure, not to the accusative case.

kumsal means beach (especially the sandy shore), and -a / -e is the dative ending, often meaning to or toward.

So:

• kumsal = beach
• kumsala = to the beach

This works because gitmek usually takes the dative case for destinations:

• okula gitmek = to go to school
• eve gitmek = to go home
• plaja gitmek = to go to the beach
• kumsala gitmek = to go to the beach

Both can refer to a beach, but the nuance is a little different:

• kumsal = sandy shore, beach as a natural stretch of sand
• plaj = beach, often more like a beach area used for swimming/sunbathing

In many contexts, they are close in meaning.
So kumsala gitmek and plaja gitmek can both work, but kumsal emphasizes the sandy beach itself a bit more.

It breaks down like this:

• git- = go
• -me- = negation
• -meli- = should / must
• -sin = you (singular)

So:

• gitmelisin = you should go
• gitmemelisin = you should not go / you shouldn't go

This is a very useful pattern:

• yapmalısın = you should do
• yapmamalısın = you should not do
• konuşmalısın = you should speak
• konuşmamalısın = you should not speak

Because in Turkish, verbal negation usually attaches directly to the verb stem first, and then other endings come after it.

So the order is:

• verb stem
• negative
• necessity / modality
• personal ending

For this sentence:

• git-
• -me-
• -meli-
• -sin

= gitmemelisin

This is normal Turkish structure.

Usually gitmemelisin is best understood as you shouldn't go.

It often expresses:

• advice
• recommendation
• mild warning
• something considered a bad idea

Depending on context, it can sound stronger, almost like you mustn't go, but grammatically it is usually softer than a direct command.

Compare:

• Gitme! = Don’t go! (direct command)
• Gitmemelisin. = You shouldn’t go. (advice/warning)

Because Turkish often leaves out subject pronouns when the verb ending already shows the subject.

Here, -sin tells us the subject is you (singular).

So Turkish does not need sen unless it is being emphasized.

• Gitmemelisin. = You shouldn’t go.
• Sen gitmemelisin. = You shouldn’t go. (extra emphasis)

The most neutral order is very natural:

• Güneş kremi sürmeden kumsala gitmemelisin.

Turkish word order is flexible, but the verb usually comes at the end. Other parts can move for emphasis.

For example:

• Kumsala güneş kremi sürmeden gitmemelisin.
• Güneş kremi sürmeden gitmemelisin kumsala. (less neutral, more marked)

The original sentence sounds natural and standard.

Yes, absolutely. That would also be natural.

The main difference is just vocabulary choice:

• kumsala = to the beach / sandy shore
• plaja = to the beach / beach area

Both work well in this sentence.

Yes. Turkish often uses -meden / -madan where English might use:

• without doing
• before doing in a practical sense

So sürmeden literally means without applying, but in context it naturally gives the idea:

• don’t go to the beach without applying sunscreen
• apply sunscreen before going to the beach

That is why this structure is very common and useful in everyday Turkish.