A 2-D full wavefield inversion method is presented for the processing of wide-aperture data. The diversity of information contained within such datasets may be handled in a complete manner by first matching the traveltimes of the main events and then progressing to waveform fitting of the data through explicit full wavefield modelling. Our wavefield inversion scheme is based upon a finite difference solution of the 2-D elastic wave equation in the time distance domain. The strength of adopting such an approach is the ability to generate all possible wave types within a given 2-D model (multiples, converted waves, etc.) and thus to simulate and accurately model complex seismic wavefields. The aim of the inversion is to find the 2-D P-wave velocity model that minimizes the least squared difference between the observed and synthetic data across the full range of offsets. Following extensive testing on synthetic data, the wavefield inversion scheme has been applied to wide-aperture real marine seismic streamer datasets. We present results from the synthetic testing and the wavefield inversion of wide-aperture real data out to 12 km offset that was recorded on a single streamer. Even though current computational restrictions allow only a small subsection of the data to be analysed, these examples demonstrate the potential value of wide-aperture 2-D full wavefield inversion.