The MV Hebrides had 76 people on board when a technical failure meant it was unable to slow down at Lochmaddy harbour, North Uist, on 25 September.
The vessel struck both harbour pontoons as well as rocks on the seabed.
CalMac said it had now been repaired at dry dock in Greenock and should be back in service on Monday.
Sea trials are due to take place on Saturday. If successful, the MV Hebrides will return to the Uig, Tarbert and Lochmaddy route.
Ferries the MV Clansman and MV Lord of the Isles, which had been re-routed to provide cover, will resume normal service the same day.
Ross Moran, CalMac's general manager operations, said: "Many communities have been disrupted to a greater or lesser extent by MV Hebrides being taken out of service for dry dock repairs.
"None more so than South Uist, which temporarily lost its daily return service from Lochboisdale to Mallaig with MV Lord of the Isles.
"While there has been some very understandable frustration about the situation, there has also been a much appreciated amount of understanding and support, for which CalMac is very grateful."
He added: "We thank the people and businesses of South Uist and all other communities affected by this uncertain period for their great patience, and we apologise for the undoubted inconvenience.
"We look forward to successful completion of sea trials for MV Hebrides on Saturday and a return to normal service across the network on Monday."
A Caledonian MacBrayne ferry damaged when it crashed into a harbour has been repaired and is expected to resume service on Monday.