The Finn, who won the 2007 world championship for the Scuderia, is now in his first week working at Ferrari since agreeing to return.
Ferrari has confirmed Raikkonen arrived at Maranello this morning and will spend three days working with the engineers and running in the simulator.
"It's good to be back at work," said Raikkonen.
"I began by getting used to all the new systems and procedures that we will use this year.
"From this point of view, the simulator is really very useful."
Raikkonen missed the final two races of the 2013 season in order to have back surgery.
He first visited Maranello the week before Christmas, and will stay until Wednesday on his latest visit.
But despite the fact he has not driven for Ferrari since the end of 2009 and the major rule changes for this season, Raikkonen insists his workload is not too intense.
"It's true there's lots to do but the workload is not much different to what it was in the past," said Raikkonen.
"For me, these days in Maranello are also an opportunity to be with the team and spend a bit more time with my many friends here."