Work to move gas, water, electricity and telecom pipes and wires to make way for tram tracks will cause traffic disruption in the city from next month.
Princes Street from Frederick Street westwards will be down to one lane of traffic as will St Andrews Square from the start of February for 16 weeks.
Shandwick Place will be completely closed for 19 weeks from mid-February.
Work will start at the west end of Princes Street from mid-April at the Lothian Road junction until August.
Council-owned Transport Initiatives Edinburgh (Tie) said temporary traffic management measures would be put in place to ensure the disruption to public and private transport in the city would be minimised.
Traffic will be diverted from the west end of Edinburgh and George Street will become a key arterial route for traffic flowing through the city centre.
Work, centred around Charlotte Square, Hope Street, Frederick Street and St Andrews Square, has already begun.
Willie Gallagher, executive chairman of Tie, said: "This programme of work will complete the majority of utility diversions in the centre of Edinburgh.
"The work will be completed before August so as not to impact on the Edinburgh Festival.
"The work will of course mean temporary traffic diversions will be put in place.
"We have modelled a number of options to develop the best solution that provides optimum flow for both public transport and other traffic.
"Tie will continue to work with the business community in this part of Edinburgh to ensure that practical issues including access and service are resolved and that Edinburgh remains open for business as the work continues."
Cllr Phil Wheeler, Edinburgh City Council transport convener, said: "It is imperative that Edinburgh remains open for business throughout the construction work."
Iain Coupar, Lothian Buses marketing director, said: "It is important that the travelling public are kept informed of all changes to routes, services and bus stops.
"We will ensure that the right messages are communicated to them in advance and during the works."