The feature includes 20 content layers, containing information contributed by the world's leading scientists, researchers, and ocean explorers including several from the UK.
"We have a much more detailed bathymetric map (the ocean floor), so you can actually drop below the surface and explore the nooks and crannies of the seafloor in 3D," said John Hanke, director of Google Earth and Maps, on an official Google blog.
"While you're there, you can explore thousands of data points, including videos and images of ocean life, details on the best surf spots, logs of real ocean expeditions, and much more."
Executives said the new functionality was an important breakthrough for the product, given that the world's oceans cover more than 70 percent of the planet's surface and contain 80 percent of all life on Earth.
"In discussions about climate change, the world's oceans are often overlooked despite being an integral part of the issue," said Google CEO, Eric Schmidt. "About one-third of the carbon dioxide that we emit into the atmosphere ends up in the oceans. Furthermore, biodiversity loss in our oceans in the next 20-30 years will be roughly equivalent to losing an entire Amazon rainforest, but this goes unnoticed because we can't see it. This is why today's launch of Google Earth 5.0 is so important - it gives us an opportunity to change everyone's perspective."
Other new features in Google Earth 5.0 include Virtual Time travel, which allows you to see historical Google Earth satellite imagery; Mars 3D, which introduces high resolution images of the planet's terrain; Touring, which allows you to create narrated tours of imagery and content; and GPS Tracking, a satnav tool allowing runners, cyclists and hikers to visualise their routes.