We have studied 1/f noise in critical current Ic in h-BN encapsulated monolayer graphene contacted by NbTiN electrodes. The sample is close to diffusive limit and the switching supercurrent with hysteresis at Dirac point amounts to ≃5 nA. The low frequency noise in the superconducting state is measured by tracking the variation in magnitude and phase of a reflection carrier signal vrf at 600–650 MHz. We find 1/f critical current fluctuations on the order of δIc/Ic≃1E−3 per unit band at 1 Hz. The noise power spectrum of critical current fluctuations SIc measured near the Dirac point at large, sub-critical rf-carrier amplitudes obeys the law SIc/Ic²=a/f^β where a≃4E−6 and β≃1 at f>0.1 Hz. Our results point towards significant fluctuations in Ic originating from variation of the proximity induced gap in the graphene junction.