Josh Weinstein, corporate treasurer of parent company Carnival Corporation & plc, will become president of Carnival UK following the planned departure of current CEO David Noyes in July after six years in the business.
Weinstein will be responsible for overseeing both P&O Cruises and Cunard.
He will report to Stein Kruse, currently CEO of the Holland America Group, who is promoted to group CEO of Holland America Group and Carnival UK.
Noyes will remain in his role until July 18 to ensure a smooth transition. The Southampton-based Carnival UK executive team will then report to Weinstein, following his move to the UK in April. Carnival UK chairman David Dingle will continue in his role.
A graduate of the University of Pennsylvania and the New York University School of Law, Weinstein, 43, joined Carnival Corporation 15 years ago as an attorney in the corporate legal department before assuming the role of corporate treasurer.
Carnival Corporation CEO Arnold Donald said: "Some time ago, David Noyes advised me that he wished to step down as CEO Carnival UK during 2017 to spend more time with his family.
"David has excelled in his time as CEO of Carnival UK and has planned a smooth and effective transition.
"We greatly appreciate his leadership, his team spirit and the many important contributions he has made to our success."
Donald added: "In his current role, Josh Weinstein has been a strong contributor to the company's successful results.
"I am confident he will do a great job in his new role and continue to build on our strong legacy of success in the UK. "
Donald continued: "Stein Kruse has done an exemplary job in leading the Holland America Group.
"The two groups will continue to be managed separately as they are today but will benefit from more closely aligned collaboration."
Noyes said: "I will be leaving Carnival UK as a thriving, profitable and market leading business. I know that with Josh at the helm, the company will continue to go from strength to strength as the UK cruise sector maintains its exceptional levels of growth."