The 2007 world champion is returning to the sport this year with the rebranded Lotus team after two years driving in the World Rally Championship.
He climbed aboard a two-year-old Renault car in Valencia to try and acclimatise himself to the different confines ahead of the first official test in Jerez next month.
Lotus, who raced as Renault last season, said they would try to get as many laps into Raikkonen in old machinery over the next two days.
The new Lotus will be launched on 5 February, two days before the serious work begins at Jerez as teams prepare for the Australian Grand Prix in Melbourne in March.
Teams are not allowed to test up-to-date cars outside of official sessions which meant Raikkonen could drive only an older machine using demonstration tyres.