Steven Davis, Gastón Ramírez and Emmanuel Mayuka will link up with their respective countries after this Sunday's game against Fulham.
Davis has been selected by Northern Ireland for their upcoming FIFA 2014 World Cup qualifier against Portugal.
The Saints midfielder will skipper the Green and White Army when they take on the Portuguese, who recently moved into third place in the FIFA rankings.
The game will take place at F.C. Porto's Estádio do Dragão on Tuesday 16th October, with the match kicking off at 8.45pm local time.
Ramírez is in the Uruguay squad for FIFA 2014 World Cup qualifying matches against Argentina and Bolivia.
First up for La Celeste is a trip to the Estadio Malvinas Argentinas in the Argentine city of Mendoza, where Ramírez and his teammates take on the CONMEBOL qualification leaders on Friday 12th October at 9pm local time.
Then comes another away game, this time against Bolivia at the Estadio Hernando Siles in La Paz on Tuesday 16th October with a 3pm local-time kick-off.
Mayuka has been called into the Zambia squad for a crucial 2013 Africa Cup of Nations second-leg qualifier against Uganda.
The Chipolopolo won the first leg 1-0 last month, with the winner of the overall contest progressing into next year's finals, which takes place in South Africa in January and February.
The trio join Saints teammates Danny Fox, Nathaniel Clyne, Maya Yoshida and Alberto Seidi in being called up by their respective countries.
All seven players will join up with their national squads following this weekend's games and return in time for the trip to West Ham on Saturday 20th October.