This paper describes the first attempt to infer ocean currents from the shapes of seismic streamers using real data. It demonstrates that it is feasible to infer the ocean currents, using a total least-squares solution at each shotpoint, when there is no lateral steering. There are some artefacts in the inferred currents when there is lateral steering; this is believed to be caused by errors in estimating the streamer velocity. This paper describes the residual equations that form the cost function and discusses how to choose weights in the cost function based on physical criteria. Correctly choosing weights is something of an art and requires further research to make automatic and robust.