Neath RFC said there would be 'significant improvements' to the Gnoll
Swapping posts for nets will be part of the duties of the ground staff after a deal was made to host football matches at the Gnoll, famous for rugby.
Neath RFC say sharing the Gnoll with the town's football team will lead to an upgrade of the ageing facilities.
It is hoped the Football Association of Wales will also consider staging European football games there.
The Gnoll has been home to the rugby side - known as the Welsh All Blacks - since the club formed in 1871.
The club said sharing the ground with football team, known as the Eagles, would double its use.
Fixtures will be played on alternative weekends from September.
Rugby club chairman Geraint Hawkes: "By joining forces in a ground share agreement the clubs, Neath community and surrounding areas will benefit hugely.
"There are now genuine opportunities to develop the Gnoll as its historic but ageing facilities need to be extensively upgraded to accommodate both codes."
He said work on preparing the playing surface had begun and would be followed by "significant" stadium improvements.
"The prospect of attracting European football is a truly exciting one which will bring much needed revenue into the community.
"This is yet another chapter in Neath rugby's s proud history and one that I feel is vital and in-keeping with our long term ambitions."
Eagles director Andy Dyer: "The ground share will be an opportunity for Neath Athletic to gain a presence in the heart of the Neath community.
"Our squad will gain from the upgraded facilities and ultimately both rugby and football will benefit and the share will be good for sport in the Neath community."