The RB team is fielding an all-Japanese line-up in first free practice with Iwasa joining regular driver Yuki Tsunoda in the VCARB 01 in their home round.
RB has given Iwasa the first of two mandatory rookie FP1 slots for the year, with the 22-year-old among the roster of young driver prospects that also includes reserve driver Liam Lawson and F2 driver Isack Hadjar.
This year Iwasa competes in Japan's domestic Super Formula series, scoring ninth on his Suzuka debut with Mugen as the top rookie.
Previously Iwasa won the 2020 French F4 championship, which led to an F3 campaign with Hitech and two years in F2 with DAMS.
Last year he scored three wins on his way to fourth in the championship, with too many non-scores to be a factor in the title fight.
While RB is no longer a pure Red Bull junior team, CEO Peter Bayer told Autosport that training young drivers for Red Bull was still a core task, aiming to have one younger driver alongside a more experienced hand at the Anglo-Italian outfit.
RB has therefore ramped up its TPC (testing of a previous car) programme, which now allows drivers to privately test the 2022 cars, which are much closer to the current specification than the 2021 generation that was allowed last year.
"Oscar Piastri is the best example. He ran I don't know how many hundreds or thousands of miles [with Alpine], but he came in and he understood the car," Bayer said. "He understood the dynamics, he understood the switches, and it makes such a big difference, and so it connects you fully.
“And we have a big programme actually for Liam, Isack and potentially Iwasa, and we want to make sure that we run them as much as possible also. It's interesting that the previous car [that can be tested] is a 2022 car, so it's finally a relevant car.”