An insertable anti-leaking ostomy device includes a tube having an internal end and an external end, and a first inflatable balloon positioned at or near the internal end. The device is configured to be inserted through a stoma into a patient's body, with the first inflatable balloon positioned inside the body and the external end remaining outside. After insertion, the first inflatable balloon is inflated via an inflation valve to retain the device beneath a fascial layer and to provide a sealed flow channel for effluent. In some embodiments, a second inflatable balloon is positioned at or near the external end to help funnel effluent into a normally attached ostomy pouch and reduce leakage. An applicator with a base and a plunger can facilitate insertion and deployment of the device.