Stephen Kenny's men play Portugal tomorrow night.
The Republic of Ireland are in World Cup qualifier action against Portugal tomorrow night.
The Portuguese FA have confirmed that 7,865 spectators can attend the game, which kicks off at 7.45pm Irish time.
Leixlip's Nathan Collins, Andrew Omobamidele and Maynooth's Mark Travers are all included in the 25-man panel.
It's the first of three games in quick succession for the boys in green, and there will be 25,000 admitted to the Aviva Stadium for the matches against Azerbaijan and Serbia on Saturday and Tuesday.
Stephen Kenny's squad will train at the Estádio Algarve this evening ahead of the match against Portugal.