The family of Nicola Furlong are travelling to Tokyo, where the main suspect for her murder is due make his first court appearance on Friday.
The 19-year-old US citizen, who cannot be named in Japan because he is a minor, is charged with strangling 21-year-old Ms Furlong in a Tokyo hotel in May.
It will be her father Andrew's second trip to Japan since the killing.
Nicola’s mother Angela and her sister Andrea are also making the journey to Tokyo.
Last month, Mr Furlong met detectives investigating his daughter's death and visited the rural university where she was studying business and Japanese.
James Blackston, 23, who was detained for sexually assaulting Ms Furlong's Irish friend, was rearrested on a separate charge last week.
