Xylocopa caerulea is a relatively large species, reaching an average size of. The species is sexually dimorphic, with the thorax region of the females having striking blue color and the male's thorax looking more brownish green. The sides of the abdomen and first abdominal segments are also covered by a similar, albeit finer and thinner coat of blue hairs. The reflectance spectrum of the thorax of femaleXylocopa caerulea has a broad band in the blue wavelength range, with a trough around 600 nm, indicating the presence of a pigment that strongly reduces reflection in the red wavelength range.
Xylocopa caerulea will burrow into trees to make their nests. They usually are solitary, but sometimes multiple bees will share a common entry hole. They create honey which is mixed with pollen to create ambrosia or bee bread. This species will place the bee bread in a wooden chamber which they then lay their eggson top of. The bee bread serves as a food source for their larvae.