Perth Seaplanes chief executive Mac McCormack said they would look for an alternative landing site.
�We will approach the Department of Transport to get approval to land in the estuary between the two bridges,� Mr McCormack said.
Mr McCormack intends to fly tourists from Perth to Mandurah.
He flew down to Mandurah earlier this month to have the noise of the plane tested.
However, the ocean waters off Seashells Beach were too choppy for the plane to land.