Corgannwg, the largest choir in the competition with 117 singers, includes pupils and former pupils of Ysgol Gymraeg Bro Morgannwg in Barry.
Formed in November, the choir was set up to celebrate the school’s 25th anniversary.
Catrin Williams, musical director, said: “We also have prospective pupils as well as teachers and former teachers, as well as some grandparents and other friends of the school.”
A total of 800 singers took part in a single competition for choirs at the National Eisteddfod, which welcomed 14 groups including community choirs, specially formed choirs, and those new to Eisteddfod competition.
Each choir presented two contrasting own-choice pieces of up to eight minutes.
The competition was held as part of the Eisteddfod’s opening weekend.
When asked if the choir would continue after the Eisteddfod, Ms Williams said: “We’ll talk about it.”
Other participants included the Landsker Singers from Haverfordwest, Pembrokeshire, founded in 1990 by Edmund Walters and Shirley Williams.
The choir is made up largely of members from the farming community along the Landsker line, the imaginary line that divides Pembroke linguistically, and half of the choir speak Welsh and the other half are non-Welsh speaking.
Conductor Benjamin Richards said that for this year’s Eisteddfod, the choir focused on performing more material in Welsh.
He said non-Welsh-speaking members “enjoyed the challenge” of learning a piece entirely in Welsh.
On the Saturday of the Eisteddfod, ten choirs competed in a separate event organised by Cymdeithas Eisteddfod Cymru.
All participating choirs had previously competed in at least two smaller Eisteddfodau across Wales.
That competition was won by Côr Bryn Owain from Cowbridge, with Cor Godre’r Garth and Côr y Gleision, both from Cardiff, taking second and third place respectively.
