Human exploration of the ocean remains extremely limited, especially when it comes to the deep ocean. Here are key points summarizing how much of the ocean has been explored:
- Only about 5% of the entire ocean has been explored and charted by humans, meaning 95% remains unknown
- When focusing specifically on the deep ocean floor (areas below 200 meters depth where sunlight fades), the explored portion is even more minuscule. A recent 2025 study found that humans have visually documented only about 0.001% of the deep seafloor , an area roughly the size of Rhode Island
- This tiny explored fraction is based on over 43,000 deep-sea dives recorded since 1958 and includes estimates of private dives
- The majority of deep-sea observations have been concentrated within 200 nautical miles of a few countries (United States, Japan, New Zealand), indicating a very limited and biased sampling of the global deep ocean
- While sonar mapping has covered about 25% of the ocean floor's contours, detailed visual and biological exploration remains far less, with deep-sea conditions (high pressure, darkness, cold) making exploration extremely challenging
- Experts emphasize the urgent need for more exploration to understand the deep ocean's ecosystems, especially before activities like seabed mining proceed, due to potential irreversible environmental impacts
In summary, while we have mapped some features of the ocean floor, the vast majority of the ocean-particularly the deep ocean-remains unexplored and unseen by humans, with only about 0.001% of the deep seafloor visually explored to date
