Pinus pinea, the Stone Pine grows to 12-20 metres (39-66 ft) in height, and can exceed 25 metres (82 ft) height. In youth, it is a bushy globe, in mid-age an umbrella canopy on a thick trunk, and, in maturity, a broad and flat crown 40-60 metres (130-200 ft) in width. The bark is thick, red-brown and deeply fissured into broad vertical plates.

Foliage: The flexible mid-green leaves are needle-like, in bundles of two, and are 10-20 centimetres (3.9-7.9 in) long (exceptionally up to 30 centimetres (12 in)). Young trees up to 5-10 years old bear juvenile leaves, which are very different, single (not paired), 2-4 centimetres (0.79-1.6 in) long, glaucous blue-green; the adult leaves appear mixed with juvenile leaves from the fourth or fifth year on, replacing it fully by around the tenth year. Juvenile leaves are also produced in re-growth following injury, such as a broken shoot, on older trees.

Cones: The cones are broad ovoid, 8-15 centimetres (3.1-5.9 in) long, and take 36 months to mature, longer than any other pine. The seeds (pine nuts, piñones, pinhões, pinoli, or pignons) are large, 2 centimetres (0.79 in) long, pale brown with a powdery black coating that rubs off easily, and have a rudimentary 4-8 millimetres (0.16-0.31 in) wing that falls off very easily. The wing is ineffective for wind dispersal, and the seeds are animal-dispersed, originally mainly by the Azure-winged Magpie, but in recent history, very largely by humans.