The appeal for vital funding was launched after it was announced in May that the PS Waverley, built in 1946, would not sail in 2019.
It attracted donations from more than 8,000 members of the public and £1million from the Scottish Government, to help carry out an urgent refit of the ship's aged boilers.
The Waverley's new boilers are currently being built by Cochran's Ltd in Annan, Dumfries and Galloway and are due to be completed in February next year.
The work required on the ship will involve the removal of the iconic twin funnels to allow access to the boiler room.
The ship will be moved from Glasgow to Greenock, Inverclyde under tow in January, where the major "open-heart surgery" will take place.
The full works are expected to take around four months to complete, allowing Waverley to undertake her regular cruises around the west of Scotland, the Mersey, Bristol Channel, South Coast and the Thames in 2020.
Paul Semple, Waverley Excursions general manager, said: "Thanks to the fantastic generosity of so many people and organisations we are now able to push 'full ahead' with Waverley's boiler refit which will be the most substantial refit since her rebuild was completed back in 2003.
"I would like to thank everyone who has donated to the appeal and supported our efforts to save the last seagoing paddle steamer in the world."
The recent appeal for cash has been the most successful in the ship's preservation career.
But ongoing support will be required given the annual cost of dry docking and refit.
Mr Semple added: "The trustees of the Waverley charity believe that ongoing charitable giving must now form a greater part of Waverley's long-term operational survival to ensure she remains in service.
"We are deeply grateful to all those who have helped this year, and in the months and years ahead, will ask those who care and who are able to help, to add Waverley to their permanent thoughts."