The APLNG Mainline (also known as the APLNG Pipeline or the APLNG Gladstone Pipeline) is a transmission pipeline in central Queensland. The pipeline is owned by Australia Pacific LNG (APLNG), which is a joint venture between Origin Energy, ConocoPhillips and Sinopec. Origin Energy is the operator of the pipeline and also operates APLNG’s coal seam gas fields.

The APLNG Mainline is approximately 365 km in length, with a nominal diameter of 1050 mm, and a nominal base capacity of 1,500 TJ/day. 

The APLNG Mainline transports gas from APLNG’s coal seam gas fields in the Bowen-Surat basins near Wandoan in central Queensland to APLNG’s LNG processing facility at Curtis Island near Gladstone. It connects to the Condabri and Woleebee Laterals, as well as to the Queensland Gas Company (QGC) mainline via the Wandoan Interconnect Facility. The Narrows Crossing portion of the APLNG Mainline comprises of three sections totaling approximately 11 km and extends from the last mainline valve (ML4) on the main gas transmission line to Curtis Island.

The APLNG Mainline is currently a non-scheme pipeline, and is subject to the access regime for non-scheme pipelines under Part 10 of the National Gas Rules (NGR). It was previously subject to the access regime for non-scheme pipelines under the former Part 23 of the NGR, which was replaced by Part 10.

On 19 December 2022, the AER granted the APLNG Mainline and Narrows Crossing Pipeline a Category 1 exemption under Part 24 of the NGR to apply until 1 March 2028. 

On 26 February 2018, the AER granted the APLNG Mainline with a 12 year Category 1 and Category 2 exemption under the former Part 23 of the NGR under the name APLNG Mainline and Narrows Crossing. Due to reforms to the NGR, these exemptions transitioned to a Category 1 exemption under Part 10 of the NGR.

In 2012, the Commonwealth Minister (being the relevant minister) granted a 15 year non-coverage determination for the APLNG Mainline.

Construction of the APLNG Mainline was completed in 2014.