Australia Post is the successor of the Postmaster-General's Department, which was established at federation in 1901 to formalise colonial postal services.

It was common for early settlers to ride many miles out of their way to deliver neighbours' mail that had been collected from informal distribution points.

Recipients paid a fixed price of one shilling per letter to collect mail from Nichols' home, with parcels costing more depending on how heavy they were.

[5] In 1967, 4-digit postcodes in Australia were introduced, in addition to the world's first mechanical processing centre, which garnered international attention.

In December 1987, 21-year-old Melbourne University student Frank Vitkovic, while experiencing a mental health crisis, entered the Australian Post building located at 191 Queen Street in Melbourne and spoke "animatedly" with an unidentified friend who worked in the building, then perpetrated what came to be known as the Queen Street massacre.

[12] However, in 2013, the corporation acknowledged that, though the strategy was successful in improving Australia Post's profitability and structure, it was insufficient in its contributions to their development as a financially self-sustaining business.

[14] In August the following year, Australia Post returned to profit with strong parcel and courier performance, and organisation re-structuring.

"[15] On 23 February 2017, Fahour announced his resignation, effective July 2017, telling media that the decision was not related to discussion of his salary.

[16] In October 2019, Australia Post completed a major rebranding project with Melbourne-based brand strategy firm Maud.

This project saw the development of a new brand identity, website and self-service platform, parcel and letter packaging, street posting boxes, staff uniforms, and a fleet of custom-designed electric vehicles, amongst others.

[18] Responding to competitive pressures, Australia Post continued to broaden its product and service range in 2019, having invested in extensive technology-based infrastructure programmes.

[21] Australia Post is self-funding and uses its assets and resources to generate profits, which can be reinvested in the business or returned as dividends to its sole shareholder, the Australian Government.

[24] Under the Australian Postal Corporation Act 1989, letters up to 250 grams are reserved to Australia Post – other people and businesses can only carry them if they charge four times the basic postage rate.

In June 2015, Australia Post announced that in view of mounting losses, and especially the accelerating decline in its letter delivery service, it would reduce its workforce by 1,900 over three years through voluntary redundancies.

The longest air service delivers to remote communities in the outback covering 1,790 km (1,110 mi) over two days.

[citation needed] The last remaining mailboat service operates still on the Hawkesbury River to the north of Sydney, out of Brooklyn ― The Riverboat Postman.The most isolated Post Office is located 217 km (135 mi) from Onslow, Western Australia, 32 km (20 mi) from the nearest customer.

Managing Director, Ahmed Fahour noted this tied in with a worldwide decline of letter volumes over the past seven years.

The basic postage rate for a small letter has increased over the years due to inflation but influenced in recent years by a complex interplay between Australia Post's monopoly over small items, and need to provide service to all Australian addresses at the mandated basic rate.

[55] Since about 2005, larger letters have been charged a round multiple of the base postage rate, which is helpful to customers if they do not have stocks of the more expensive stamps.

A large letter, including packaging, cannot be more than 20mm thick or larger than 260x360mm, otherwise it will be considered a parcel, which as of July 2023 costs a minimum of $10.60 (up to 500 grams).

Australia Post also offers personal finance products, such as car and travel insurance[63] and currency conversion.

It also provides complete end-to-end supply chain capabilities, from manufacturer (domestic or international) to consumer with integrated logistics services and a broad range of distribution options to track and trace deliveries.

[70][71] On 23 December 2003, Australia Post and Qantas went into a joint venture to acquire StarTrack from the company's founder, Greg Poche.

[77] Complaints by individuals and the LPO Group[78] about Australia Post's business practices in relation to its franchised retail outlets – Licensed Post Offices (LPOs) and Community Postal Agencies (CPAs) – resulted in the Australian Senate conducting an inquiry in 2014.

The inquiry's unanimous report included recommendations for increased payments and the establishment of an independently chaired stakeholder forum.

[82] On 2 November 2020, the CEO Christine Holgate announced resignation, due to increasing pressure from the Prime Minister Scott Morrison and Communications Minister Paul Fletcher to investigate further into the gifting of four senior executives with the total of $20,000 AUD worth of Cartier watches.

Increasing media attention also contributed to her decision, as it was causing much "debate and distraction" and was negatively impacting her health.

[84] During Senate Estimates hearing on 22 October 2020, Ms Holgate defended her decision, saying "We are a commercial organisation, it was a recommendation from our chair that these people get rewarded".