The two-dimensional wideband direction-of-arrival ( DOA) estimation plays an important role in achieving the underwater acoustic communication and positioning integration. The two-sided correlation transformation (TCT) algorithm is one of the most popular techniques for high-resolution wideband DOA estimation. However, it is only suitable for one-dimensional DOA estimation under uniform linear arrays, and it has large computational burden. In this article, a fast 2D wideband DOA estimation algorithm with low computational complexity is proposed for arbitrary planar arrays based on the extension and improvement of the simplified TCT (STCT) algorithm. The proposed algorithm performs the matched pre-processing on the array output data by using the known waveform of the underwater acoustic communication synchronization signal, which effectively compresses the number of frequency bins required for the focusing transformation. Therefore, the computational complexity of the focusing transformation is reduced. The accelerated particle swarm optimization (APSO) in cosine domain is used to search for two-dimensional spectral peaks, which significantly reduces the searching complexity while maintaining high searching accuracy. Compared with the pure extended STCT algorithm, the proposed algorithm maintains high DOA estimation accuracy, and the accuracy is about 0. 02° when the signal-to-noise ratio is 20 dB. But, the computational complexity is much lower than the former. Simulation and experiment results evaluate the advantages of the proposed algorithm.