A new and distinct grapevine variety ‘Sugrafortysix’ is characterized in that it produces large, red and ovoid berries and has a large bunch size. The berries of ‘Sugrafortysix’ are firm and very juicy. The new variety ‘Sugrafortysix’ is characterized by an earlier harvest date compared to ‘Scarlet Royal’ (U.S. Plant Pat. No. 16,229).