Sugiro a opção "travel in time" para se dizer "viajar no tempo" em inglês. Observe a seguir dois exemplos de uso retirados de publicações internacionais, feitos por falantes nativos do idioma. Tanto em British English quanto em American English.
''One of these is, if sometime in the future, we learn to travel in time, why hasn't someone come back from the future, to tell us how to do it.'' [Space and Time Warps - Stephen Hawking]
So it would seem that: (1) it's not only the men in the family who can travel in time, and (2) they actually can travel into the future. [Revista Time - USA]
P.S. ainda existe a opção "travel through time".
''For example, when Tim goes into a closet and clenches his fists, he occasionally travels through time and merges with Past-Tim who, for some reason, is also standing in the same closet.'' [Revista Time - USA]
Bons estudos. Compartilhe.