Largest gas pipelines by capacity

Rows are ranked as GEM reports them. Several of the largest entries are national or regional transmission networks, not single pipes, and a few look large for the diameter and length beside them (compare the columns before relying on one row); the page does not correct them. For the longest routes see longest pipelines, and for one network against the LNG fleet pipeline gas versus LNG.

A project that lists several sizes, such as a trunk line with branches, is counted once, at its widest. The sizes are as GEM states them, in inches or millimetres per row, converted here; before 2026-11-07 this site read every size as inches, which overstated the millimetre ones.

Which gas pipeline has the largest reported capacity?

Transcontinental Gas Pipeline (United States) at 172 bcm/y among operating pipelines in the November 2025 release. That is the capacity GEM reports for the project, which for a network can span many lines, so it is not the capacity of a single pipe.

Why is one pipeline left out of the lists?

South Tunisia Gas Project Pipelines reports 6,132 bcm/y, which is more than 10 times the next-largest figure of any pipeline in the tracker, so it is left out rather than ranked first. It is named on this page and in the data-quality checks; the figure may be in a different unit in the source.

Can I add these capacities up?

No. Capacity is a design figure for each project, not a flow, and the tracker does not say whether projects overlap in what they cover, so a total could count the same pipe twice. The page shows rows, never a total.

How many pipelines report a capacity or a diameter?

Of 2,975 operating pipelines, 1,777 report a capacity and 2,269 a diameter. The rest are not in the lists below and are not estimated.