The summer's main event is Euro 2012, kicking-off on June 8, and Croatia begin their preparations on Friday night with a friendly against Estonia in Zagreb.
Luka Modric, Niko Kranjcar and Vedran Corluka are all in the Croatia squad.
Harry Kane, who finished the season so impressively on loan at Millwall, is with the England Under-19 squad in the Elite Qualifying Round of the UEFA U19 Championship.
England take on Slovenia, Montenegro and Switzerland and must top the group to make it into the finals.
On Saturday, England's senior team have their first friendly under new boss Roy Hodgson with Jermain Defoe and Scott Parker aiming for minutes against Norway in Oslo.
Sandro is with the Brazil squad for a friendly against Denmark while Rafa van der Vaart faces Bulgaria with Holland.
Giovani is in the Mexico squad for friendlies against Wales on Sunday and Bosnia next Thursday.
There are another batch of friendlies in June before Euro 2012 while away from Europe, Steven Pienaar and Bongani Khumalo are in the South Africa squad for World Cup 2014 qualifiers against Ethiopia and Botswana.