A surgical seal system is adapted for use with a cannula assembly having a cannula housing and a cannula sleeve extending from the cannula housing. The surgical seal assembly includes a seal assembly and an adapter assembly. The seal assembly is mountable to the cannula housing. The seal assembly includes a seal housing and a seal defining inner portions adapted to form a substantial seal about an instrument with a first cross-sectional dimension. The adapter assembly includes an adapter body adapted for releasably coupling to the seal housing of the seal assembly. The adapter body has an adapter seal and a tether. The adapter seal is adapted to form a substantial seal about an instrument with a second cross-sectional dimension less than the first cross-sectional dimension. The tether is mountable to the cannula sleeve thus securing the adapter assembly to the cannula.