The network upgrade from East Coast Buses will include the creation of a new express route running from North Berwick to the city centre.
Connections between Musselburgh, Haddington and Dunbar are also set to be improved through the introduction of the 106 service, a new direct link.
A total of 11 new jobs will be created as a result of the changes, which the firm said were a “direct response” to growing customer demand.
The announcement follows investment by East Coast Buses in the refurbishment of its Musselburgh headquarters.
General manager Mark Heritage said: “When we stepped in to take over these services last year our expectations were very modest.
“As a socially responsible operator, we knew that we would be protecting lifeline connections for residents and commuters.
“Since then, though, we’ve been absolutely delighted with the positive response from the local community.
“Thanks to our exceptional team we’re now in a position to introduce even better services for the East Lothian community.”
Other changes will include the creation of a new link on the number 107 between the High Street and Asda in Dubar, while the 113 service will be extended to West Granton in order to provide new connections to Edinburgh College campuses.
Further improvements will also be implemented on the Nighthawk service.
Changes to the fare structure for two Lothian Country Buses services (113 and 104) are also in the pipeline to bring prices into line with the rest of East Coast Buses operation.
Full details will be made public on April 3, with East Coast Buses would be announcing further investment ticketing plans later this year.
It comes after Lothian Buses announced they would be bringing in a new airlink bus between north Edinburgh and the airport in their annual network update.
From April 23, the new 200 service will run from Ocean Terminal to Edinburgh Airport via Clermiston and Muirhouse.
Lothian Buses will also be creating jobs for 45 new drivers and a further ten apprentice engineers.
Other changes including route extensions to destinations including Fort Kinnaird Retail Park, Edinburgh Park and the Gyle shopping centre.
Richard Hall, managing director of Lothian Buses, said the changes came in response to public feedback and that he was “delighted” to be able to expand the firm’s offering.
However critics hit out at plans to cut back on the number 42, service which links north Edinburgh to the rest of the Capital.
A campaign against the move is expected to launch over the coming weeks, with concern raised over the potential impact on congestion, pollution and trade.