Adults are about 1 inch long; larvae are rarely seen. Adults resemble large bumble bees but have a characteristic bald, shiny, black abdomen and a black bald spot on the dorsal thorax. Males have a yellow patch on the face above the mandibles (jaws).

Carpenter bees are solitary but may appear in numbers where nesting sites are available, such as exposed structural wood. Females carve dime. sized tunnels and galleries in sound or damaged wood, entering laterally against the grain and following along the grain inside. Galleries are a series of brood chambers for individual bee larvae and 5 or 6 are created in a line. Female eggs are laid and provisioned with pollen and nectar and sealed sequentially. Male eggs are laid in the galleries closest to the entrance. Carpenter bees emerge in reverse order, with males emerging first, followed by females. Carpenter bees, like all other bees, are pollinators.

Carpenter bees do not cause health risks to humans, but females can sting if handled roughly. Male bees are quite visible as they guard the nesting females from intruders and other males. It is common to see males chasing each other and investigating humans that enter their territory; however, males are harmless to humans. The galleries carved in structural wood by female bees become problematic over time as tunnels may extend as many as 10 feet and be multileveled. Structural wood becomes unsound through continuous damage or intrusion of wood-rotting fungi or other wood-destroying insects.