An ostomy output diversion device is used to cover and seal closely around a patient's stoma, to divert stoma effluent output through the device, through a drain tube and into a container or reservoir, temporarily eliminating the need of an adhesive-based ostomy pouching system. The ostomy output diversion device is placed over the person's stoma, with the base ring surrounding the peristomal skin, the adjustable inner tube is retracted until the base ring is centered over the stoma, the body support strap is then placed over the device to secure it to the patient's body, the inner tube with stoma-sized adapter is then extended over the stoma, the patient applies the desired pressure against the skin, then secures the stoma-sized adapter in place with the pressure adjustment lock. The device may also include an ostomy pouch mounting ring for attachment to an ostomy pouch, and a disposable receptacle.