A sea of pink could be seen around Lake Burley Griffin on Saturday morning as students from St Clare's College came out in protest against a proposal to introduce boys at their school.
Year 12 student Isobel Hill said the atmosphere was "magnetic" with students, alumnae, parents and teachers all united in their cause.
"Everyone there was so spirited and they all had such kind things to say about St Clare's," she said.
Fellow year 12 student Amelia Richardson said they would organise further protest actions if the archdiocese continued to pursue the idea of turning St Clare's College into a coeducational school.
"We didn't want it to come across that it's like we hate boys, we're anti guys. It's honestly, it's nothing to do with that," she said.
"We've become independent women. The school has built us into the people that we are. We don't want it to change that reputation and I don't want these younger girls to miss out on the opportunity that we have."
The proposal to change St Clare's College to a coeducational model is the most contentious proposition in the Catholic Archdiocese Canberra Goulburn Education plan to offer more coeducation high school places in Canberra's south.
The archdiocese is also investigating whether two of its existing primary schools - St John Vianney's at Waramanga and St Jude's at Holder - could be developed into a coeducational preschool to year 12 or year 7 to 12 school.
The executive director declined to be interviewed about the proposals which are causing much discussion in the Catholic education community.
Mel Hendrie has a daughter who would be starting at St Clare's in 2028, the earliest date for any changes to the school's enrolment policy. Her daughter attended one of the open days and was sold on going to the school.
She said the coeducation proposal feels like a short-term solution to gain about 300 more enrolments at the expense of upsetting the families who want an all-girls school.
"It feels a little bit like a money grab... Without more context from Catholic education, it feels like they're just scrambling in a sense to make some quick money, and then think about how they're going to do a more long-term option in the future."
Chatter at the school gate has been all about the St Clare's proposal and the idea of creating a Cathedral Precinct with St Clare's College, St Bede's at Red Hill, St Benedict's at Narrabundah and St Gregory's in Queanbeyan.
But Ms Hendrie said the proposals feel rushed and lacking in detail which means parents are filling the void with speculation.
"I feel like it is lacking. It's kind of like they've been squirreling away for a while, and then have just come to the community to say, 'Here's all of our possible ideas and our grand plans' and some of them are really large bombs."
Ms Hendrie said redeveloping St John Vianney's Primary School into a coeducational college would be a better option to support families in Molonglo Valley, Tuggeranong and the inner south.
Merici College assistant principal Renee Taylor said there continued to be strong demand for single-sex Catholic education in Canberra with the Braddon school reaching its enrolment quota for 2027.
"We continue to be astounded by the demand both within the ACT but also within NSW families. Merici has a lot of families from both the ACT and New South Wales who come to us because they are seeking, amongst many reasons,... a single sex education for their daughters."
Part of the proposed Cathedral precinct plan is to offer transport between Queanbeyan and the Canberra schools in the precinct.
About 600 secondary students from Queanbeyan and surrounds already attend Catholic schools in the ACT.
Merici College operates four dedicated buses within the ACT but Mrs Taylor said more transport options would be very welcome for NSW families.
"I've been at Merici for 10 years now, and throughout that time, we've enrolled as far south as places like Michelago, as far north as Yass,... out to Braidwood, as well."
The discussion paper suggests that if St Clare's were to go coeducational, more places would be needed at Merici College, which is approaching capacity.
"We will respond, as all schools will, to whatever the enrolment policy moving forward is for the archdiocese," Mrs Taylor said.
"We are very much aware that no decisions have been made in reference to St Clare's, nor some of the other primary schools who have been named as a part of the potential precinct approach that Catholic education have proposed."
The archdiocese is eyeing off a plot of land in the Stromlo Reach development in Denman Prospect for a new school. But with lots of competition from non-government schools, it's not guaranteed to become part of the Catholic system.
The chair of Weston Creek Community Council Simone Hunter said it was exciting to hear of plans to potentially expand St Jude's or St John Vianney's to high school.
"I understand there's quite a high demand for for Catholic education in the area. They've been doing some great work at St Jude's and at St John Vianney's, which are well-established primary schools within the region," she said.
"From my perspective, it would make it makes sense to have an expansion into that secondary school space."
St Jude's had 492 students at the start of this year and has had steady enrolments thanks to the early learning centre.
St John Vianney's is one of the smallest Catholic schools, with 175 students as of February, but has grown its enrolments over the past five years.
Ms Hunter said St Jude's could be a better option for a high school since St John Vianney's was next to Mount Stromlo High School.
"Mount Stromlo High School is a really good public school. I don't know what the sense would be of having two high schools next to each other... The Holder site seems a bit a bit better for servicing the Molonglo Valley as well."
St Jude's Community Council chair Gemma Cabot said parents would work through their ideas in preparation for the planned consultation meeting in November.
"The parents of St Judes understand that our children need Catholic secondary school options on the south side and the discussion paper presents interesting opportunities.
"We are keen to share our insights on what possible arrangements would suit families best and have input into the planning process."
