Es mejor que llegues a la terminal con tiempo, por si cambian la puerta de embarque a última hora.

Because es mejor que normally triggers the subjunctive.

In Spanish, when you give advice, make a recommendation, or express a value judgment like it’s better that..., the verb in the following clause usually goes in the subjunctive:

• Es mejor que llegues... = It’s better that you arrive...
• Es importante que salgas temprano.
• Conviene que reserves antes.

So:

• llegues = present subjunctive
• llegas = present indicative
• llegar = infinitive

After es mejor que, Spanish wants the finite verb in the subjunctive, so llegues is the correct choice.

It comes from the verb llegar in the present subjunctive.

Steps:

1. Start with the yo form of the present indicative: llego
2. Remove the -o: lleg-
3. Add subjunctive endings for -ar verbs:
   • yo: llegue
   • tú: llegues
   • él/ella/usted: llegue
   • nosotros: lleguemos
   • vosotros: lleguéis
   • ellos/ellas/ustedes: lleguen

Notice the spelling change:

• not lleges
• but llegues

That u is there to keep the hard g sound.

Because after por si, Spanish normally uses the indicative, not the subjunctive.

Here por si means in case:

• Lleva un paraguas, por si llueve.
• Sal pronto, por si hay tráfico.
• Llega con tiempo, por si cambian la puerta.

So:

• por si cambian = in case they change
• por si cambien = not the normal choice here

This is one of the things English speakers often find tricky, because in case can feel hypothetical, but Spanish still usually uses the indicative after por si.

It’s an unspecified they.

Spanish often uses the third person plural with no stated subject when the speaker means something like:

• they
• people
• the staff
• the airline
• the airport
• whoever is responsible

So por si cambian la puerta de embarque means:

• in case they change the boarding gate

It does not need an explicit subject like ellos. In fact, leaving it unstated sounds more natural here.

Con tiempo means with enough time to spare, in good time, or simply early enough.

In this sentence:

• llegar a la terminal con tiempo = arrive at the terminal with enough time before departure

It does not literally mean with time in a word-for-word English sense. It’s an idiomatic expression.

Compare:

• Llega con tiempo. = Arrive with time to spare.
• Sal con tiempo. = Leave early / leave with enough time.
• Hazlo con tiempo. = Do it in advance / don’t leave it too late.

Yes, in many situations, but the meaning is slightly different.

• temprano = early
• con tiempo = with enough time to spare

So:

• Llega temprano focuses on being early
• Llega con tiempo focuses on having enough margin, enough extra time in case something happens

In an airport context, con tiempo is especially natural because it suggests a buffer for delays, security, gate changes, and so on.

Because llegar a is the normal structure for arrive at/to a place.

• llegar a la terminal
• llegar al aeropuerto
• llegar a casa

Here the sentence is talking about the movement toward the destination, so a is needed.

By contrast:

• estar en la terminal = to be in the terminal
• esperar en la terminal = to wait in the terminal

So:

• llegar a la terminal = arrive at the terminal
• estar en la terminal = be in the terminal

Yes. Puerta de embarque is the standard expression for boarding gate.

Breakdown:

• puerta = door/gate
• embarque = boarding

So:

• la puerta de embarque = the boarding gate

In airports, Spanish often uses this full phrase where English simply says gate.

Examples:

• Tu puerta de embarque es la B12.
• Han cambiado la puerta de embarque.

It means at the last minute or at the last moment.

It does not usually mean literally at the final hour on the clock.

So in this sentence:

• cambian la puerta de embarque a última hora = they change the gate at the last minute

This is a very common expression in Spanish.

Examples:

• Siempre avisa a última hora.
• Cancelaron el vuelo a última hora.

The comma separates the main recommendation from the reason/precaution clause.

Main idea:

• Es mejor que llegues a la terminal con tiempo

Extra precaution:

• por si cambian la puerta de embarque a última hora

The comma helps readability and reflects a natural pause. In a sentence like this, it is very normal.

Yes, but the structure changes slightly.

Both are possible:

• Es mejor que llegues a la terminal con tiempo.
• Es mejor llegar a la terminal con tiempo.

Difference:

• Es mejor que llegues... directly addresses you and sounds more personal
• Es mejor llegar... is more general, like it’s better to arrive...

So both are correct, but que llegues is more directly giving advice to someone.

Yes, usually la terminal means the terminal building.

So:

• el aeropuerto = the airport in general
• la terminal = the specific terminal building

That matters because airports can have more than one terminal.

Examples:

• Nos vemos en la terminal 4.
• Ya estoy en el aeropuerto, pero no en tu terminal.

Because Spanish often omits subject pronouns when the verb form already shows who the subject is.

Here:

• llegues clearly indicates tú
• so tú is unnecessary

Spanish usually prefers:

• Es mejor que llegues...

rather than:

• Es mejor que tú llegues...

The pronoun tú would only be added for emphasis or contrast.

Yes, it sounds completely natural in Spain.

Nothing in it is unusual or strongly regional. A few especially natural features are:

• con tiempo
• puerta de embarque
• a última hora

These are all very normal in Spain, and also widely understood elsewhere in the Spanish-speaking world.