The larvae of the black soldier fly, Hermetia illucens, contain high amounts of protein and fat, and so are a good feed source. However, this high fat content hinders the production of such feed. The excess fat must thus be removed to enable the larvae to be used as a feedstock e.g., for aquaculture and livestock. Firstly, the use of hot water treatment as a strategy for extracting fat from dried larvae was tested. It was found that this process reduced the fat content of the raw material (from 30 to about 16%). However, the resulting product was still not suitable for feed processing. Next, the use of a carbon dioxide supercritical extraction system on crushed larvae was studied. This system time-dependently reduced the fat content to less than 6.6% and less than 4.6% after treatments for 2 and 6 h, respectively, with a pressure of 350 bar used on larval particles of 10–18 mesh in size. Therefore, subjecting 10–18 mesh crushed larval powder to carbon dioxide supercritical extraction at 350 bar for 6 h yielded a larval powder with a fat content of 5% or less. Based on this finding, this method is proposed to be a suitable alternative for further processing of larvae feedstock.