The cruise lines, which are both based in the Hampshire city, have marked its support of the annual festival by transforming the stairs of its Carnival House headquarters in the rainbow colours of the LGBT movement.
Southampton Pride takes place on 24 August and is expected to attract more than 15,000 to the celebrations, including a performance by pop group S Club.
The cruise lines have been associated with the event since its inception in 2016, with Cunard becoming the first headline sponsor and P&O being a joint sponsor last year.
Carnival UK president Josh Weinstein said: “Both Cunard and P&O Cruises have a proud and long history of welcoming LGBT guests and crew onboard our combined fleet of 10 ships. We are delighted to be participating in this event and several others around the world.”
The company is also running an internal campaign, called Summer of Happiness – My Best Me, for staff at Carnival House between May and September.
“It is focused on encouraging and supporting each and every one of our employees to be the best version of themselves and achieve their maximum potential, irrespective of gender, sexual orientation, age, ethnic background, religion or ability,” explained Weinstein.
