The Commission issued a statement on Friday describing Croatia's journey towards membership of the two areas.
"I warmly welcome Croatia in the euro and in the Schengen free travel area. From this Sunday, citizens driving to and from Croatia can start traveling without internal border controls," European Commission President Ursula von der Leyen said.
"This is a major achievement for Croatia, a symbol of its deep-rooted attachment to the EU, and a symbolic moment for the euro area as a whole. This is a proud moment for the EU, Croatia and its citizens," she added.
Commission Executive Vice-President Valdis Dombrovskis said that "this is an important step for Croatia to mark its full European integration, and important for the entire European Union," while Vice-President Margaritis Schinas added: "This is a milestone in Croatia’s European path and a fully deserved one. My heartfelt congratulations to all Croatians!"
Commissioner for Economy Paolo Gentiloni said that "this New Year will be an unforgettable one for the Croatian people."
"What a historic milestone both for Croatia and for the European Union as a whole! Perhaps no EU Member State has made such an incredible journey over the past three decades: from the horrors of war in the 1990s, to EU membership in 2013 and now set to enjoy two of the most tangible benefits of EU integration," Gentiloni said.
Commissioner for Home Affairs Ylva Johansson, noted that each new Schengen member makes the EU stronger. "I am proud of the work the Commission and Croatia have done together so that Croatians can benefit from this historic step forward. In that respect, I remain personally committed to both Romania and Bulgaria becoming members in the near future."