The heads are expected to congregate next Wednesday on the Maes at the festival site in Mold, north Wales, to talk about the alternative to shutting down schools as a "knee-jerk" reaction to falling pupil numbers.
The meeting has been organised by UCAC, the only Welsh medium teaching union, as it continues to campaign against the closure of schools it believes are vital to small Welsh communities.
The gathering is being held just weeks after the Welsh Local Government Association admitted in the document entitled Let Government Commence: The Political and Service Challenges of the Assembly Third Term that school closures were being made with a lack of clear understanding over what constitutes an acceptable level of surplus places (TES Cymru July 20). It also said local authorities should be considering other options than closure but are prevented by legal barriers.
Gruff Hughes, general secretary at UCAC, said there was a lack understanding of any alternative to closure, particularly by local councillors.
"When a school closes, it closes forever. Local authorities must be completely sure that this the correct course of action," he said.
Meriel Parry, headteacher of both Ysgol Tregarth and Bodfeurig in Bangor, Gwynedd, is expected to talk about how the schools were succeeding under her sole leadership, despite the added workload and pressure.
Sion Mason-Evans, head of Llanwnnen County Primary in Ceredigion, which is threatened with closure, will tell how bringing together four small schools had benefited pupils by offering them "more expertise from staff and a wider range of extra-curricular and social experiences".
Meryl Pierce, governor at Ysgol Pant Pastynog in Denbighshire, which was once threatened with closure, will also tell a survival story.
"In 2005 there were only 26 pupils on our register, but by September 2007 the number will be 48, almost double," she said before the meeting.
The Welsh Local Government Association predicts there will be 46,000 fewer pupils in Wales by 2010. Calls have been made by leading academics for more central intervention into the tackling of surplus places in Wales.
Labour has always favoured school closures as a solution to surplus places but Plaid Cymru, which is now part of the coalition government, has always fought to keep them open, especially those in small Welsh-speaking communities in the rural heartlands.