Formal:
* Até mais tarde: This is the most common and literal translation of "until later."
* Até breve: This means "until soon" and can be used in place of "until later" if you'll see the person again shortly.
* Até a próxima: This means "until next time" and is more formal than "até mais tarde."
Informal:
* Até: This is a very casual way to say "see you later."
* Falou: This is a very informal way to say "see you later" and is commonly used among friends.
Note: "Falou" is a slang term that can be considered rude or disrespectful in some situations.
The best way to choose which phrase to use is to consider your relationship with the person you are talking to and the context of the situation.