The sale of Condor Ferries to Brittany Ferries and an investment fund has been completed.
The ferry firm, which carries about a million passengers every year between Portsmouth, Poole, Guernsey, Jersey and St Malo, was put up for sale in 2018.
The purchase was announced in November, but had to be approved by regulators before it could be finalised.
"The new shareholders share our vision for maintaining and developing ferry services," said Condor boss Paul Luxon.
"We will be working with them, along with local stakeholders, on long-term plans that include fleet replacement and investment."
Founded in 1964 by Channel Island businessmen Peter Dorey and Jack Norman, Condor operated passenger services between the Channel Islands and France.
The ferry network was expanded in 1987 when the company launched the first route connecting the Channel Islands with the UK.
Condor currently operates with four ships, including the high-speed vessels Rapide and Liberation, all-weather Commodore Clipper and freight ship Commodore Goodwill.
The operator, which has its headquarters in Poole and is registered in Guernsey, carries more than 200,000 passenger vehicles and 100,000 freight vehicles to and from the islands each year.
The consortium that has bought the firm is made up of Columbia Threadneedle European Sustainable Infrastructure Fund and Brittany Ferries, which operates between the UK, France, Spain and Ireland.
Chief executive Mr Luxon said: "As a company, Condor's immediate focus is to continue preparing for the season.
"We fully recognise we play a vital role in supporting the visitor economies of Jersey and Guernsey alongside our commitment, for over 70 years, to providing essential freight services and travel options for islanders."
Christophe Mathieu, CEO of Brittany Ferries which is the minority shareholder of Condor, said: "We are committed to working closely in the months and years to come to ensure the best level of service to customers and support to our friends and colleagues in the Channel Islands.
"This will be business as usual for Condor."