The first section, attached to a pylon which was partially submerged, was freed from the sunken piece and floated to the wall where it was lifted out by the harbour crane.
The work was carried out using the new ferry platform as an operating base. Then when the divers had raised the sunken section using airbags, and supported by straps from the crane, the fire and rescue service, led by Mark Gaudion, used two portable pumps to empty the water before it was hoisted onto the Commercial Quay.
The States of Alderney blamed the windy weather for the sinking but local boat users said this was not the first time the pontoons had sunk.
The States Harbour Authority hopes to replace the wharf after the repairs are completed, which could take several days.
During the operation, the French ferry Manche Isles Express from nearby Dielette was using the harbour for manoeuvring exercises, and had to be moored on the eastern side of the Quay.