Lawson will sport #30 at the United States Grand Prix in his first race since replacing Daniel Ricciardo at RB.
Last year, Lawson ran #40 in his limited schedule as an injury replacement for Ricciardo.
That number has since been used by Ayumu Iwasa in his Free Practice outing at the Japanese Grand Prix.
Formula 1 has long issued temporary numbers for drivers who are exempt from the career number rules.
Oliver Bearman, for example, this year raced with #38 for Ferrari at the Saudi Arabian Grand Prix and then #50 with Haas at the Azerbaijan Grand Prix.
Lawson ran a variety of numbers in karts but stuck with #30 for the lion’s share of his junior career.
His move into car racing saw him run #30 in Formula First (Formula Vee).
He most recently used #30 in 2021 during his DTM campaign in the Red Bull-backed AF Corse-run Ferrari 488 GT3.