Display omitted •Heterogeneous honeycombs with bio-inspired line defects are designed and analyzed.•Structure with octagon-pentagon defects own 12.7% higher Young’s modulus than the benchmark.•The structure with pentagon-trigon defects exhibit about 56.5% higher SEA than the benchmark.•Composite-lattice honeycombs own non-uniform collapse bands under compression. Taking inspiration from geometric defects in hexagonal lattices existing in nature (beehive and graphene), this work explains how defects in the form of channels can improve the effective Young’s modulus and specific energy absorption properties of hybrid-lattice hexagonal honeycombs under compression due to non-uniform collapse band behavior and strain delocalization. The results reveal that in terms of effective Young’s modulus, honeycombs with octagon-pentagon and pentagon-trigon defected cells outperform the benchmark structure by roughly 13% and 20%, respectively. In terms of specific energy absorption (SEA), all composite-lattice honeycombs show superior behavior to the benchmark honeycomb, especially the pentagon-trigon defective honeycomb with about 56.5% higher SEA. The novel structures show promising design prospects for applications in various industries, especially automotive and construction with cost-effective advantage in customized or low-volume production cases.