Hello Chanmu. ^^

There are different ways to say goodbye and don't worry about politeness. As long as you said you're going, that's being polite enough already. ^^

Here are 9 ways to say goodbye though. ~~

1) "See you later" or "see ya later" : This becomes more casual when you use "ya" instead of "you."

2) "See you soon" or "see ya soon" : This is similar to the example above. It can be used to indicate that you want to or plan to meet with the person again soon.

3) "Take care" : This could be formal or casual, but is usually used with people you know or care about. You might use this in an email or written letter.

4) "Take it easy" : This is not used now as much as it was used in the 1980's and 1990's. However, it is casual and means "take care."

5) "Gotta go!" This is used in casual situations when you want to escape the conversation quickly and you don't want to go through a longer or more sentimental goodbye.

6) "Talk to you soon" : This is used more often in writing emails or on the phone than in daily spoken interactions. It is usually casual.

7) "See you next time" : This is used when you know you will be returning to a specific place and you will see the person when you come back.

8) "Catch ya later" : This is used very casually between friends or acquaintances.

9) "Have a good one" : This means, "have a nice day" and is used casually, but it could be used between strangers, friends, colleages, or family members.

CORRECTIONS:

How to say goodbye?

I met foreign friends in Korea at Language Exchange meeting.
So I met their first time. I want to say "It's time to go home". My subway is finished at 11:50PM.
So, how to say goodbye?
>> How would I say goodbye?

I met some foereign friends at a language exchange meeting here in Korea. It was the first time I met them but I had to go home since the last train en route to my home was at 11:50PM. So, how do properly say goodbye?

It's time to go home. I had a nice time. See you, next time.
>> I had a good time but it's time for me to go home. I'll see you around.
Or

A subway will be finished soon. I have to go home. See you :) Good bye.
>> I have to catch the last train home. See you soon.

If you have a great idea, just comment this note, pleas.
I want to know useful expression.

>> If you have other ideas, just place your comments. I would like to know other useful expressions.

How to say goodbye?

I met foreign friends in Korea at a Language Exchange meeting.
So, I met them for the first time. I want to say "It's time to go home." My subway is finished will be here at 11:50PM.
So, how to say goodbye?

It's time for me to go home. I had a nice time. See you, next time.

Or

The subway will be here soon. I have to go home. See you :) Good bye.


If you have a great idea, just comment on this note, please.
I want to know useful expressions.