Port Depth & Vessel Draft Explained

Depth is the single most important physical fact about a port. A ship can only call somewhere if there is enough water beneath it — at the entrance, along the approach, and at the berth. That is why every port page on The Port Index lists several different depth figures. Here is what each one means and why they differ.

Draft vs. depth — the key distinction

Depth describes the water (how deep it is at a given point). Draftdescribes the ship (how far below the waterline its hull extends when loaded). For a vessel to enter safely, the available depth must be greater than the ship’s draft, plus a safety margin called under-keel clearance.

The main depth figures, explained

• Channel depth — the depth of the dredged approach channel a vessel travels through to reach the harbour. This is often the limiting factor: a deep berth is useless if ships cannot reach it.
• Anchorage depth — the depth where vessels wait at anchor before entering, often offshore. Deep anchorage lets large ships hold position safely.
• Cargo pier depth — the depth alongside the quay or pier where a ship actually berths to load and discharge. This determines how heavily laden a vessel can be when it ties up.
• Oil terminal / LNG terminal depth — depth at specialised liquid-bulk berths, which often need to be deeper to handle large tankers.

Maximum vessel draft

Some ports also publish a maximum vessel draft— the deepest a ship’s hull is allowed to sit when calling at that port. It is effectively the port’s “up to this deep” limit, derived from the shallowest constraint along the route in and the berth itself. Where the World Port Index records no figure, our pages show it as “not reported” rather than guessing.

Why tides matter

Depths are not fixed. The tidal range— the difference between high and low water — can add or subtract several metres. Many ports schedule the largest, deepest-drafted vessels to arrive and depart on a high tide, a practice called working the “tidal window.” A port with a big tidal range can handle deeper ships at high water than its charted depth alone suggests.

Putting it together

When you look at a deep-water hub like the Port of Rotterdam, Busan, or Felixstowe, the combination of a deep channel, deep berths, and a manageable tidal window is exactly what lets them serve the world’s largest container ships. You can compare depths across ports throughout the directory.