In this talk we discuss an inverse boundary element method for thelocalization of moving sound sources. The sound sources are assumed tobe distributed along the boundary of the domain, whereas measurementsare performed inside the domain. We further assume that the directionof the movement as well as its velocity are constant. For this reason,we can apply the 2.5D boundary element method to reduce thethree-dimensional problem to multiple two-dimensional problems.The computation of the effects of the sound sources on the soundpressure at the measurement locations is computationally costly,because a single boundary problem needs to be solved for eachindividual sound source. If the number of measurement points issmaller than the number of sound sources, we can reduce thecomputational complexity by making use of the reciprocity law. Thereciprocity law relates these effects with the sound pressure at theboundary elements induced by artificial sound sources located at themeasurement positions.