Almost 800 students, staff and priests packed Wiseman Park, Gwynneville, yesterday to celebrate the amalgamation of Wollongong's St Francis Xavier school with St John Vianney's of Fairy Meadow.

The two schools were joined yesterday by "little sister" school St Brigid's Primary.

The amalgamation is not due to be completed until 2012, but the three schools already appeared to be one, as students got stuck into some friendly competition as part of a gala sports day.

St John Vianney's student Sahri Brown said she was excited about getting a new uniform and classmates, while St Brigid's student Aydn Bektasovski said he was looking forward to making lots of new friends at the enlarged school.

Gwynneville and cathedral parish administrator Father Ron Peters said there was a "good buzz" in the air about the amalgamation, while the gala day was all about forming close relationships.

"We saw this social day as not only for the children, but for the staff and parents to get together and get to know each other better," he said.

St Brigid's principal Jennie Werakso said the three schools had about 220 years of Catholic education between them, and a shared heritage.

"Today is about celebrating the relationship between our schools," she said.

The fun in the sun was timed to coincide with Catholic Schools Week, which celebrates the achievements of more than 600 Catholic schools throughout NSW and in the ACT.

St Francis Xavier will also celebrate 100 years of education tomorrow with a centenary Mass to be led by Bishop Peter Ingham and Fr Peters.

The school has invited past staff members, students and community members who have had an association with the school to join the celebration.

Anyone wanting to get involved can find more information on the school's website at www.sfxdow.catholic.edu.au.