Learn Hardcore Spanish (Spain): Cuando camino por la orilla, siento la arena fría en los pies. - When I walk along the shore, I feel the cold sand on my feet.

Camino por la orilla = I walk along the shore (you move following the line of the shore).
Camino en la orilla would sound more like I walk at the shore as a general location, and is much less natural here.

For walking along something (a street, a river, the shore), por is the normal preposition:

Camino por la playa, por el río, por la ciudad.

What exactly does orilla mean? Is it just “shore”?

Orilla literally means edge / border / shore. In this context it’s the water’s edge on the beach, where the water reaches the sand.

In everyday beach context in Spain:

La playa = the whole beach.
La orilla = specifically the edge where the waves come in and out.

So caminar por la orilla suggests walking right where the water meets the sand, not up by the towels and umbrellas.

Why is there no yo before camino and siento?

In Spanish, the verb ending already tells you who the subject is, so the subject pronoun is often omitted:

camino → I walk
siento → I feel

You only add yo if you want to emphasize it (contrast or stress):

Yo camino por la orilla, pero mis amigos se quedan en la toalla.

In this neutral sentence, leaving out yo is the most natural choice.

Could I say Cuando estoy caminando por la orilla instead of Cuando camino por la orilla?

You can say Cuando estoy caminando por la orilla, and it’s grammatically correct, but it’s not necessary.

Spanish uses the simple present much more than English to talk about:

actions that are happening now
general habits

So Cuando camino por la orilla can mean both:

When I walk along the shore (as a general habit)
When I’m walking along the shore (in that situation)

The progressive estoy caminando is only used when you really want to stress the action as ongoing right now.

Why does siento mean “I feel” here and not “I’m sorry”?

Sentir has several meanings, and context tells you which one is intended.

To feel (physically or emotionally):
- Siento la arena fría en los pies. → I feel the cold sand on my feet.
- Siento miedo. → I feel afraid.
To be sorry / to regret:
- Lo siento. → I’m sorry.
- Siento llegar tarde. → I’m sorry for arriving late.

In your sentence, siento is followed by a physical sensation (la arena fría en los pies), so it clearly has the meaning “I feel”, not “I’m sorry”.

Why is it la arena fría and not la fría arena?

Spanish typically places adjectives after the noun:

la arena fría = the cold sand
un coche rojo = a red car

You can say la fría arena, but that word order is more literary / poetic or adds a bit of emotional or stylistic emphasis.

In normal, neutral speech, la arena fría is the standard and most natural order.

Why is it fría and not frío?

Adjectives in Spanish must agree in gender and number with the noun they describe.

la arena is feminine singular → fría must also be feminine singular.
- la arena fría ✅
- la arena frío ❌

Another example:

el agua fría → the cold water (agua is grammatically feminine but takes el in the singular)
las piedras frías → the cold stones (feminine plural).

Why is it en los pies and not en mis pies?

Spanish often uses the definite article (el / la / los / las) with body parts, especially when it’s clear whose body we are talking about.

So instead of saying:

I feel the cold sand on *my feet → *Siento la arena fría en mis pies,

Spanish normally says:

Siento la arena fría en los pies.

Because the subject is I (camino / siento), it’s automatically understood that the feet are my feet. Saying en mis pies is not wrong, but it sounds more emphatic or contrastive than natural here.

Could I say por la playa instead of por la orilla?

Yes, but the image changes a bit.

Camino por la playa: I walk on/around the beach in general (anywhere on the beach).
Camino por la orilla: I walk along the water’s edge, where the waves reach the sand.

If you specifically imagine your feet near the water, por la orilla is the more precise and evocative choice.

Is there any difference between en los pies, bajo los pies, and entre los dedos de los pies?

Yes, they focus on slightly different images:

en los pies = a general contact sensation on your feet.
- Siento la arena fría en los pies.
bajo los pies = literally under my feet, emphasizing what is underneath when you step.
- Siento la arena fría bajo los pies.
entre los dedos de los pies = between my toes, a more specific, detailed image.
- Siento la arena fría entre los dedos de los pies.

All are correct; the original sentence just chooses the most general and simple version: en los pies.

Can I change the order and say Siento la arena fría en los pies cuando camino por la orilla?

Yes, that word order is perfectly correct and very natural.

In Spanish, either order is fine:

Cuando camino por la orilla, siento la arena fría en los pies.
Siento la arena fría en los pies cuando camino por la orilla.

The meaning is the same; you just decide which part you want to highlight first (the situation or the feeling).

Why are la orilla, la arena, and los pies all with articles? Could I omit them?

In Spanish, you generally must use an article with singular, countable, specific nouns, and often even with general ones.

Here they all refer to specific, real things in the situation:

la orilla → the shore (of this beach)
la arena → the sand (understood from context)
los pies → my feet

If you removed the articles, the sentence would sound very unnatural or simply wrong:

✗ Cuando camino por orilla, siento arena fría en pies. (incorrect)

So in this sentence, all three articles are necessary.