An Bord Pleanala has refused plans by Inishbofin Ferry to build accommodation for staff on the island.
The plans would've seen new ferry staff accommodation, offices and equipment storage built at a site on the east side of Inishbofin.
The plans were rejected by county planners last year - prompting an appeal to An Bord Pleanala, which has now rejected the plans for staff accommodation on similar grounds.
They found that Inishbofin Ferry failed to demonstrate a housing need at the specific location, and permission would contribute to "encroachment of random rural development".
They also held that the proposed development would not effectively blend into the sensitive rural landscape.