The Ospreys will play five games at Neath's Gnoll ground in 2005/6.
Their other 13 scheduled home matches will be at the new Morfa stadium on the outskirts of Swansea.
The Neath-Swansea region will split their matches equally between the Gnoll and St Helen's this year whilst the Morfa is under construction.
"The Ospreys will be able to manage commercial interests, whilst keeping a strong element of regional rugby," said joint managing director Mike Cuddy.
The Neath-Swansea prefix to the region's name could also play a smaller part in future as the Ospreys try to attract support from around Port Talbot and Bridgend.
These areas were under the umbrella of the Celtic Warriors, but have been redistributed after the regional side was disbanded.
"With the enlarging of the region we're considering marketing ourselves as 'The Ospreys', and we'll consider changing the badge to the mask logo," joint managing director Roger Blyth told BBC Wales Sport.