There has been a growing interest to the materials with broken time-reversal and inversion symmetry, which can support non-reciprocal superconducting currents [1]. This search for an intrinsic superconducting diode has so far resulted in devices that typically show a few percent difference between the magnitudes of the supercurrent flowing in the positive and negative directions. We show that required time-reversal symmetry breaking can be achieved in multiterminal Josephson junctions [2], resulting in supercurrent rectification approaching 100%.