Ocean Floor Map

St. Helena Bay depth map

Bay: average depth about 17 m, deepest 51 m (GEBCO_2026 grid).

Tap or scroll to load the interactive map

Sea level todayDrag the slider to lower the sea and see the land that would appear.

Sea level in metres below today’s. A simple bathtub model: it lowers the sea everywhere by the same amount and does not simulate how the water would really drain.

Key

Sea depth

  • Deeper than 6,000 m
  • 4,000 to 6,000 m
  • 2,000 to 4,000 m
  • 1,000 to 2,000 m
  • 200 to 1,000 m
  • Shallower than 200 m (the continental shelf)

Land height

  • Land up to 500 m
  • 500 to 2,000 m
  • Above 2,000 m

Drain the oceans

  • Seabed exposed when the sea is lowered A dashed white line marks today’s coast.

How to read the map. Darker blue is deeper water. Tap anywhere to see how deep the sea is there, or how high the land is, and the nearest named undersea feature. Depths come from the GEBCO_2026 grid, which in most of the deep ocean is predicted from satellite measurements of the sea surface rather than surveyed by ship, and the map’s tiles are coarser than the grid, so narrow trenches read shallower on the map than their true depth. Not for navigation.

St. Helena Bay at a glance

  • 17 maverage depth
  • 15 mmedian depth
  • 51 mmaximum depth
  • 44 km²water area

St. Helena Bay is a bay. Inside its outline the GEBCO grid has about 44 km² of water, with an average depth of about 17 m (the middle value is 15 m) and a maximum of 51 m, found at 31.86° S, 18.24° E.

Open the map at the deepest cell and tap to read the depth.

How deep is each part of the St. Helena Bay?

The bar splits the St. Helena Bay's water by depth. Each colour is a depth band, and the shares add up to 100%.

  • 0 to 200 m: 100%
  • 200 to 1,000 m: 0%
  • 1,000 to 4,000 m: 0%
  • 4,000 to 6,000 m: 0%
  • below 6,000 m: 0%

Named features near the deepest point: Agulhas Basin (1,153 km), Walvis Ridge (1,371 km), Ewing Seamount (1,371 km), Discovery Seamounts (1,953 km).

The St. Helena Bay if sea level dropped

The slider on the map lowers the sea in steps. This table shows how much of the St. Helena Bay's water would be land at each step.

Sea level lowered byBecomes landShare of its water
10 m9 km²20%
20 m32 km²73.3%
50 m44 km²100%
80 m44 km²100%
120 m44 km²100%
200 m44 km²100%
500 m44 km²100%
1,000 m44 km²100%
2,000 m44 km²100%
3,000 m44 km²100%
4,000 m44 km²100%
6,000 m44 km²100%

A simple bathtub model: it lowers the sea everywhere by the same amount and does not simulate how water would really drain.

Nearby seas

Nearest by the centre of each outline. All oceans and seas

Frequently asked questions

How deep is the St. Helena Bay?

On average about 17 m in the GEBCO grid (the middle value is 15 m). The deepest cell inside its outline is 51 m, at 31.86° S, 18.24° E.

How big is the St. Helena Bay?

About 44 km² of water inside its Natural Earth outline, counted from the grid cells that are below sea level.

How much of the St. Helena Bay would be land if sea level dropped?

With the sea 10 m lower, about 9 km² (20%) of its water would be land. At 6,000 m lower, 100% would be. This is a simple bathtub model that lowers the sea evenly everywhere.

Data: depths from the GEBCO_2026 grid, statistics worked out inside the Natural Earth outline of the bay. See data sources and licences. The GEBCO Grid should NOT be used for navigation or for any other purpose involving safety at sea.

All oceans and seas · Undersea features · Drain the oceans

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