have a safe trip
Other than the related answers listed below, you can also use this Chinese proverb:
一路顺风 yi(1) lu(4) shun(4) feng(1) --> have a smooth journey
旅途平安 [lǚ tú píng ān]
boa viagem
Turvallista matkaa!
"Bezpiecznej podróży!"
旅行怎么样
khair nal jao
"Želáme Vám bezpečnú cestu"
eka suraksita yatra hai
ασφαλές ταξίδι [asfales taxeethi]
旅途愉快/Lǚtú yúkuài
The Chinese translation of have a nice trip in Chinese is simply have a nice trip. This statement is usually said to the people who are travelling.
Have a safe journey = heb een veilige reis