How soon is it safe to masturbate after a vaginal hysterectomy?

Depends: If the method of masturbation is external (clitoral) stimulation, you could do this as soon as you feel up to it. It's generally recommended to not put anything into the vagina for 6-8 weeks. I would certainly discuss with your doctor before putting anything into the vagina.

Depends: If there were not complications, infections, hemorrhage or health problems, a female stimulating the clitoris to orgasm probably would be safe a week after the surgery. Pelvic engorgement, muscle contractions, vaginal elongation, and physiologic effects of the orgasm could cause some discomfort soon after this surgery. I would get the opinion of the operating surgeon. Certainly 2 weeks out -ok.

Depends: The general recommendation is "nothing in the vagina for 4 weeks" after a vaginal hysterectomy. So masturbation with penetration should wait for the full 4 weeks. If only clitoral stimulation, with no penetration, is employed then it would likely be safe after 1 to 2 weeks. The main concern would be for any straining that could disrupt the vaginal cuff.