zibin no syukkouzikoku ni ouzite, hurikae wo erabu.

次便 literally means the next service/run/departure.

The word 便 is used for scheduled transportation services, such as:

• flights
• buses
• ferries
• delivery services

So 次便 often means:

• the next flight
• the next ferry
• the next scheduled service

Because this sentence also uses 出港, it strongly suggests a ship or ferry context, so here it is probably the next boat/ferry service rather than an airplane.

The の links two nouns together.

• 次便 = the next service
• 出港時刻 = departure time from port

So:

• 次便の出港時刻 = the departure time of the next service

You can think of A の B here as B of A or A’s B.

This is a very common noun-linking pattern in Japanese.

出港時刻 is a compound noun made of:

• 出港 = departure from port
• 時刻 = time

So 出港時刻 means port departure time or more naturally departure time in a ship/ferry context.

A learner might compare it with:

• 出発時刻 = departure time in a more general sense
• 出港時刻 = specifically departure from a port

So the choice of 出港 tells you this is probably about a vessel, not a train or ordinary bus.

に応じて means according to, in response to, or depending on.

In this sentence:

• 次便の出港時刻に応じて = according to the departure time of the next service
• or depending on the departure time of the next service

It shows that the action in the main clause changes based on that condition.

Structure:

• noun + に応じて

Examples:

• 予算に応じて選ぶ = choose according to your budget
• 年齢に応じて内容を変える = change the content depending on age

So here, the thing you choose changes depending on the next departure time.

Because 応じる naturally takes に when it means to correspond to, to respond to, or to be based on something.

So:

• A に応じて B = B in accordance with A

This is just the standard pattern for this expression. It is best learned as a set phrase:

• 〜に応じて

rather than trying to translate the に by itself.

振替 can mean things like:

• transfer
• substitution
• replacement
• rebooking
• switching to another service

In transportation contexts, it often refers to being moved to another available service, such as:

• another ferry
• another flight
• another train

So in this sentence, 振替 probably means something like a rebooking/transfer option or an alternative service.

Very often in real Japanese, the full phrase might be something like:

• 振替便 = replacement service / alternate flight or ferry

But here it is shortened to just 振替 because the context already makes the meaning clear.

The direct object of 選ぶ is 振替.

• 振替を選ぶ = choose a transfer/rebooking option

Japanese often omits extra words when they are obvious from context. So instead of saying something longer like:

• 振替便を選ぶ = choose a replacement service

it may simply say:

• 振替を選ぶ

In English we often want a more explicit noun, but Japanese frequently leaves that implied.

Japanese often omits the subject when it is understood from context.

So this sentence does not explicitly say:

• who chooses
• who is affected

Depending on context, the hidden subject could be:

• you
• the customer
• the staff member
• the system/user

This is very normal in Japanese, especially in:

• instructions
• menus
• booking systems
• manuals
• short written prompts

It sounds somewhat like a short written instruction or interface phrase rather than a fully fleshed-out conversational sentence.

The dictionary-form verb 選ぶ at the end can be used in:

• UI text
• manuals
• procedures
• headings
• concise instructions

A more conversational sentence might include more context, such as:

• 次便の出港時刻に応じて、振替便を選びます。
• 次便の出港時刻に応じて、振替を選んでください。

So the original is natural, but it feels compact and functional.

The comma marks a pause and separates the condition from the main action.

So the sentence is divided like this:

• 次便の出港時刻に応じて、 = depending on the departure time of the next service,
• 振替を選ぶ。 = choose a transfer/rebooking option.

The comma is not absolutely required in every case, but it helps readability, especially when the first part is a longer modifying phrase.

By itself, 次便 could refer to many kinds of scheduled services, including a flight.

However, 出港 specifically means leaving port, so once you see 出港時刻, the context points to a ship or ferry.

So:

• 次便 alone = next service / next flight / next ferry, depending on context
• 次便の出港時刻 = strongly suggests the departure time of the next ferry or vessel

That is a good example of how surrounding words narrow down the meaning in Japanese.