An adapter is disclosed for an ostomy coupling. The adapter provides a floatable coupling characteristic to an ostomy body fitment that has a non-floatable coupling part. The adapter comprises a first coupling part for attaching to the non-floating coupling part of the body fitment, a second coupling part for releasably attaching to an ostomy appliance, and a flexible collar between the first and second coupling parts. The flexible collar permits the second coupling part to be displaced away from the first coupling part, thereby creating a space for an ostomate to manually brace the second coupling part against an attachment force when an appliance is fitted.