What the numbers mean
Most of the seabed still waits for a detailed map.
Seabed 2030 reported 28.7% coverage in April 2026. That leaves 71.3% still outside the detailed map. Broad maps already show the whole seafloor; the missing piece is finer detail.
Read the sourcesA blue map can conceal missing detail
NOAA explains that satellite data give us a broad picture of the entire ocean floor. Small undersea mountains and wrecks can still be missing. Detailed surveys often use multibeam sonar: equipment on ships that sends sound toward the seabed and measures its return. A map's usefulness depends on the detail it can resolve. [2]
The map grows when people contribute
The April 2026 update added almost five million square kilometres of data over the previous year. Seabed 2030 reported contributions from 220 organisations, combining newly collected and previously unshared datasets. Some gaps close through new expeditions; others close when existing measurements become part of the common map. The resulting GEBCO grid is publicly available. [1]
Mapping is the start of exploration
A depth map helps researchers choose where to send an underwater robot for a closer look. It can suggest a habitat, but it cannot identify every animal living there or explain how they interact. Mapping a place, seeing it directly and understanding its ecosystem are separate steps. Each leaves more questions to investigate. [2]