Japanese Thunberg pine can reach a height of 40 m, but rarely reaches this size outside its natural range. The needles are in fascicles of two with a white sheath at the base, 7-12 cm long; female cones are 4-7 cm long, ecamose, with small tips at the end of the scales, taking two years to mature. Male cones are 1-2 cm long in clumps of 12-20 at the tips of spring growth. The bark is gray on young trees and small branches, changing to black and silver on larger branches and the trunk; becoming quite thick on older trunks.