The Barcelona talisman scored the winner for his nation in the 2010 World Cup final and helped La Roja win back-to-back European Championships in 2008 and 2012.
In addition, Iniesta's situation at Camp Nou has been resolved with the signing of a 'contract for life', and the 33-year-old acknowledges that he is aware of his age "and everything it entails".
Iniesta told Spanish outlet Sport: "I am realistic. There is a great chance this World Cup will be my last event with the national team.
"I am aware of the moment, my age and everything it entails, but we will see how things develop.
"There are many months still to go until the World Cup and hopefully everything will go well so that I can be in Russia."
Iniesta made his debut for Spain in May 2006 in a friendly against Russia, going on to win 121 caps.