Abstract Due to the variability of the radiated signal of the sonar targets, passive sonar target classification is a challenging problem in the real world application. Adaptive Mel-frequency cepstral coefficients (MFCCs) and multi-layer perceptron (MLP) approaches are proposed, including cepstral features to alleviate dataset's dimension and MLP network to adapt the variability in changing condition. In spite of the capabilities of MLP networks, low classification accuracy, and getting stuck in local minima are the main shortcomings of MLP networks. To overcome these shortcomings, this paper proposes the use of the newly introduced salp swarm algorithm (SSA) for training MLP network. In order to investigate the efficiency of the proposed classifier, four high-dimensional benchmark functions, as well as an experimental passive sonar data set, are employed. The designed classifier is compared to gray wolf optimizer (GWO), biogeography-based optimization (BBO), interior search algorithm (ISA), and group method of data handling (GMDH) in terms of classification accuracy, entrapment in local minima, and convergence speed. The results showed that the proposed classifier is more efficient than the other benchmark algorithms; therefore, the SSA classifies sonar data set as much as 0.9017 percent better than GMDH being the best results among the other classifiers.