The gardens were laid out in the 19th century by various wealthy private owners, and by the early 20th were gradually being acquired by the Scarborough Corporation, unified and opened to the public.
They were one of the resort's jewels during its heyday, but their condition has declined in recent years due to a lack of investment and patronage.
Scarborough Council officers even feared they could be lost forever to cliff erosion had they not been awarded a National Lottery Heritage Fund grant in 2019.
The restoration will include the re-opening of a long-forgotten tunnel beneath the South Cliff Lift that has been sealed for generations, as well as work on paths and surfaces to improve drainage and accessibility. Ornate historic shelters will also be repaired.
The first phase will see the building of a new community centre, named Beeforth's Hive in honour of one of the original benefactors of the gardens, George Beeforth. It will be finished by November, alongside the restoration of the listed Tugwell shelter and another shelter below the putting green.
Phase two, which begins in June, includes ground drainage, more shelter works and the fitting of a new accessible toilet block near the Clock Cafe.
The third phase will involve the restoration of the Clock Tower and Italian steps, which again are scheduled to be finished by November.
The final phase will be the re-opening of the tunnel, the building of the new play area, restoration of the Italian Gardens and new planting.
An opening event will be held in April 2022 to celebrate completion.
Scarborough councillors Tony Randerson and Jim Grieve said in a joint statement: “We are delighted that work to restore these wonderful heritage gardens, which hold a very special place in the hearts of generations of residents and visitors, gets underway this week.
“Together with our previous multi-million scheme to stabilise the cliffs, this exciting project will reignite people’s love for the gardens and make them more accessible for all.
“New facilities will sit sensitively alongside restored heritage features, which will ensure the gardens’ importance in Scarborough’s history is kept alive and relevant for many more decades to come.”
Adrian Perry from the Friends of South Cliff Gardens group added: “In 2012 when the Friends of South Cliff Gardens started out on the journey to restore the gardens we had no idea of the complexity of the task that lay ahead.
“Nobody could have foreseen the difficulties created by the pandemic, which served to further extend the preparatory process. So it is with relief that finally the finishing post is within sight and the next year will see many of our dreams become a reality.”
The contractors for the scheme are Hull-based PBS Construction Ltd, who have also worked on similar public realm projects in Bridlington.