Amanda Selby, 15, from Ashton-under-Lyne, Greater Manchester, died at Ty Mawr Holiday Park in Towyn, Conwy county, on Saturday.
Her brother Matthew Selby, 19, has been charged with her murder.
Jiu Jitsu club Kamiza Dojo said Amanda and her mother had been a big part of the club for many years.
The 15-year-old’s school, Droylsden Academy in Manchester said: “Our school family is devastated by this awful news.
“Amanda was a lovely student and she will be sorely missed by students and staff.”
Earlier, Mr Selby, of Windermere Crescent, Ashton-under-Lyne, appeared at Mold Crown Court via videolink from HMP Berwyn and spoke only to confirm his identity.
He was remanded in custody and a provisional trial date was set for 28 February. It is expected to last between five and seven days.
He is also scheduled to appear in court for a plea hearing on 29 October.
Jiu Jitsu club Kamiza Dojo said: “Our club is saddened to hear the tragic news that one of our students, Amanda Selby, has lost her life while on holiday with her family.
“The Kamiza Dojo family is truly devastated by this awful news.
“Amanda, and her mother, have been a big part of our club for many years, always turning up to support the running of the club and its students.
“We are truly heartbroken, Amanda will be sorely missed.”