How do I say "time travel" in japanese? (Please only answer if you actually already knew)
For example
"Do you think time travel will be possible (in the future)?"
"In 君の名は characters travel in time"
Etc.

Question

How do I say "time travel" in japanese? (Please only answer if you actually already knew)
For example 
"Do you think time travel will be possible (in the future)?"
"In 君の名は characters travel in time"
Etc.

Answer

時間旅行（jikan ryokou) would be the translation in Japanese, but we usually don't use it, instead we would say タイムトラベル (taimu traberu, time travel) or タイムスリップ  (taimu surippu, time slip).
"Time（タイム）", "travel（トラベル）" and "slip（スリップ）" are already recognized as Japanese words.