How do you say 'have a good trip' in Japanese?

Answer 1

There are two expressions used for this purpose but neither translate directly

1. itterasshai is for shorter trips
2. kiwotsukete is for longer absences

I'm not a native Japanese speaker, but I did grow up speaking Japanese and am fluent. I have to disagree with the particular uses of those phrases. You can use them interchangeably, most of the time. The major difference is the expectation of return, not really the duration of the trip.

A parent could say "itterasshai" to a child who is running an errand and will be back shortly, whether or not that child still lives at home. If the child no longer lives at home and is going back to his own home, only "kiwotsukete" is appropriate because there is no anticipated return. I think that that's where the misconception comes from. "kiwotsukete" could also be used even for a child going to a friends house for a little while. "itterasshai" could be used for someone going on a week long business trip or vacation because the return home is anticipated. I base this on my experience with my own parents and relatives, who are all native Japanese speakers.

I edited the original entries to reflect the proper input method, but the latter is indeed pronounced, "kyoutsukete".

Answer 2

'Have a good trip' would be translated literally toよい旅を (yoi tabi o) in Japanese, but this is not too common.気をつけてね (ki o tsukete ne) means 'take care', but would commonly be used in this situation.楽しんできてね (tanoshinde kite ne) may also be used, and means 'have fun'.