Sea Life, the global aquarium brand, is owned by Merlin Entertainments and currently operates 44 aquariums across 17 countries.
McCann Bristol has been appointed to create a global TV ad campaign to run across key markets, including the UK, Germany and Australia.
The agency said the campaign would aim to create a "sense of wonder and amazement", while seeking to educate consumers about the brand's work to conserve the world’s oceans.
McCann Bristol will work closely with the McCann Sydney office to create the campaign. Sydney Aquarium is currently undergoing a rebrand to become Sea Life Sydney, and the campaign will serve as supporting activity in the attraction's relaunch.
The aquarium is undergoing a $6.5m (£4.3m) redevelopment and will boast 650 different species, 14 new features and the world's largest collection of sharks and rays.
Sarah Taylor, global head of marketing, Sea Life, said: "McCann Bristol's creative ideas for the TV campaign really captured the excitement and wonder of Sea Life, and it was clear that they had thoroughly researched our offering – not only in the UK, but globally too.
"The insights that the company can provide us with on a global scale are just what we need to successfully roll out the TV campaign into different markets in the coming months, and in turn, attract visitors."