Abstract. We present a numerical implementation of the geodesic ray transform and its inversion over functions and solenoidal vector fields on two-dimensional Riemannian manifolds. For each problem, inversion formulas previously derived by Pestov and Uhlmann in [Int. Math Research Notices 80 (2004)] then extended by Krishnan in [J. Inv. Ill-Posed Problems 18 (2010)] are implemented in the case of simple and some non-simple metrics. These numerical tools are also used to better understand and gain intuition about non-simple manifolds, for which injectivity and stability of the corresponding integral geometric problems are still under active study.Key words. geodesic ray transform, Radon transform, tensor tomography problem, inverse problems, Riemann surfaces AMS subject classifications. 65R10, 65R32, 53D25, 44A121. Introduction. The present article discusses a numerical implementation in MatLab of geodesic X-Ray transforms of functions and solenoidal (i.e. divergence-free) vector fields and their inversion on two dimensional Riemannian manifolds with boundary.Geodesic X-ray transforms appear in problems of mathematical physics where particles travel along some curves and "gather information" along their path. Probably the best known example of geodesic ray transform is that of the Radon transform in two dimensions (also known as the X-Ray transform, as these two transforms coincide in two dimensions), which is the collection of integrals of a given function over all straight lines in the plane, corresponding to the case of a Euclidean metric. Reconstructing a function from its integrals along lines was first considered and solved in [21] and is now used every day in medical imaging. A thorough account of theoretical and numerical aspects for this transform may be found in [13]. In the Euclidean case, solenoidal tensors of any order were also explicitely reconstructed in [23].When optical rays propagate in a medium with variable index of refraction, their trajectories, no longer straight lines, come as geodesics of some Riemannian metric. In this framework, the same questions (injectivity, stability, range characterization, reconstruction algorithms, inverse problems with partial data) as for the straight line case are still under active theoretical study. To the author's knowledge, numerical simulations for these transforms remain to be documented.When the metric is simple, injectivity over functions was proved in [12] and injectivity over solenoidal vector fields was established in [1,2]. Under the same simplicity assumption, the problem was recently proved in [17] to be injective over solenoidal tensors ("s-injective") of any order, and previously in [4] under assumptions on the curvature. Independently, stability estimates were given in [26] via a microlocal study of the normal operator.