An ecological shift has populated Engraulicypris sardella as a livelihood and economic drive among fishers in Malawi. However, the paucity of biological information regarding E. sardella limits the effective monitoring and sustainable management of the fishery. This has created a heavily invested fishery in terms of the effort put into fishing, but it is poorly managed. Moreover, the current production capacity from the fishery has a negligible impact on lessening the shortfall of the national fish demand, indicating its underperformance. Therefore, the productive efficiency of Lake Malawi Chilimira fishers in exploiting E. sardella was analysed. A multi-stage sampling technique was used to sample 355 Chilimira fishers between July and October 2021. Results from the translog stochastic frontier model revealed that Chilimira fishers had an overall mean technical efficiency of 60% that ranged between 21% and 92%. This indicates that Chilimira fishers are 40% technically inefficient in exploiting E. sardella. The fishing inputs of bunt area, light emitting diode (LED) bulbs, and mesh size significantly contributed to technical efficiency, whereas boat size, fishing depth, number of hauls, and mosquito net lining significantly reduced the technical inefficiency. On average, the Chilimira fishery is operating with increasing returns to scale with bunt area, the quantity of fuel (litres), and the number of LED bulbs having positive input–output elasticity. This means that new developments in the fishery, including LED bulbs, increased bunt area, and boat size, are key factors that will improve fishing efficiency for sustainable fishery exploitation. In contrast, illegal fishing units of small bunt mesh size and mosquito net lining at the bunt threaten the sustainability of the fishery. It is, therefore, important that relevant stakeholders put policy measures in place that promote sustainable fishing effort approaches in exploiting the virgin offshore fishery to maximise catch.