The long-distance calling rates on offer were initially available by consumers dialing 1 before the area code and phone number.

A number of notable wholly owned subsidiaries operate as part of the Singtel Optus group.

[17] Other wholly owned subsidiaries of note no longer have a significant active role as individual entities.

XYZed established a network of DSLAMs inside Telstra telephone exchanges, utilising Unconditioned Local Loop services to reach end users.

To provide a killer application for this, the Australian Federal government sold subscription television licences.

[22] Government relaxation of foreign ownership restrictions paved the way for the company to be floated – with Cable and Wireless increasing its holding to 52.5%)[23][24] – and listed on the Australian Securities Exchange on 17 November 1998.

Optus purchased one of Australia's pioneer ISPs, Microplex, in 1998 to provide consumer dial-up internet services.

Optus is part of a consortium – now known as Terria – that in July 2006 announced their intention to make a combined bid to build the proposed National Broadband Network.

In October 2006, Optus announced that it would outsource 100 contracting jobs to another Singtel subsidiary, IT company NCS, in Singapore.

In August 2010, OptusNet released an upgrade of its HFC network to the DOCSIS 3.0 standard,[45] which enabled customers to access a maximum theoretical downstream bandwidth of 100 Megabits.

[46] Mobile network equipment is from Nortel, Nokia and Huawei and antennas are sourced from Andrews, RFS, Argus and Kathrein.

To remain connected, a device that is capable of running 3G at 900 MHz is now required after 2G was completely disconnected across Australia.

[51] Part-owned network infrastructure includes: Between 1994 and 2005 Optus had the naming rights to the Carlton football clubs original home ground in Princes Park.

Optus and the Government of Western Australia agreed to a 10-year naming right worth approximately A$50 million.

25 Walkinshaw Andretti United Holden ZB Commodore driven by Chaz Mostert[57] Global Telcom Awards: AI Initiative of the year Asia Communications Awards: Wholesale Operator of the Year Annual MVNOs World Congress: Most Innovative Wholesaler & People's Choice Around 22 September 2022, Optus systems sustained a significant cyberattack that resulted in a major data breach of both current and former customers' personal information, including customers’ names, dates of birth, phone numbers and email addresses, with a smaller subset of customers having their street addresses, driving licence details and passport numbers leaked.

[60] On 24 September 2022, Australian news outlets The Age and The Sydney Morning Herald reported that Optus was investigating the authenticity of a ransom demand of US$1 million made on a hacking forum.

[61] On 6 October, the Australian Federal Police announced the arrest of a 19-year-old man who had allegedly threatened 93 Optus customers by saying that he would use their information leaked in the attack to commit financial crimes, unless they paid AUD $2,000.

"[64][65][66] On 11 October, the Office of the Australian Information Commissioner launched an investigation, the aim of which is to explore the company's handling of customers' data.

[67] Early on 8 November 2023, an undetermined issue caused a nationwide outage in Optus Mobile and Fixed Internet services.

Optus Mobile customers reported that their phones showed 'SOS' on the signal indicator, which is a sign the regular network is down, but mobile phones still have access to alternate networks in the event of an emergency call by using a so-called camping mechanism; however, Optus landlines were unable to make emergency triple-zero calls.