Proton therapy (PT) is expected to benefit from real-time MRI guidance. However, the integration of MRI and PT is challenging due to the interaction between the magnetic fringe fields of the PT beamline and the B0-field of the MR scanner. In this study, we measured the magnetic fringe field of the PT beamline. The measurement data will be used to validate a finite element model. With a match to this model, we can proceed to investigate what type of magnetic shielding solution would be needed to decouple the magnetic fields of the PT and MRI systems.