A bore-scope sealing apparatus is provided for removably sealing a bore-scope opening in a turbomachine wall with a plug. The bore-scope sealing apparatus includes a bayonet coupling via which the plug is mountable to the bore-scope opening. The bayonet coupling has a projection at the plug and a corresponding recess at the bore-scope opening. A resilient retaining device is arranged at the recess being compressed by the projection in a sealing position to retain the plug in the bore-scope opening.