Sheridan Mortlock

Mortlock participated in Miss Earth Australia three times.[6]

Mortlock's first pageant was Miss Earth Australia 2019, where she won Miss Earth – Australia Air 2019. She also won the special awards of "Miss Photogenic" and "Darling of the Press."

On 4 September 2022, Mortlock won Miss Earth Australia 2022 at Hyatt Regency in Sydney, Australia, also receiving the special awards; "Darling of the Press", "Best in Swimwear" and "Best in Evening Gown". She was crowned by Miss Earth Australia 2021, Phoebe Soegiono.[7]

By winning Miss Earth Australia 2022, Mortlock was tasked to have advocacy as one of the core requirements for joining Miss Earth. Her advocacy was Action, Care, and Education (ACE). Mortlock added, "Climate change and environmental protection are all linked through webs of connection. If we change one element of the ecosystem, then it will ripple out to others. This is why we must use the pillars of ACE to make the most effective changes. Only through Caring about our environment, Educating ourselves on current environmental changes, and then taking direct Action will we be able to protect Mother Earth."[8]

The main theme of Miss Earth 2022 was ME Loves Fauna, and candidates were required to promote a creature from their country; Mortlock chose the Swift parrot . She said that according to reports, there are only 750 left which makes it a critically endangered species. She cited the habitat loss in Tasmania, which is the Swift parrots' breeding grounds, as the main reason this.

Mortlock competed with 85 other delegates from various in Miss Earth 2022.

During the course of the preliminary events, she won the following awards:

• Darling of the Press (Asia & Oceania)[9][10]
• Swimsuit Competition (Asia & Oceania)[11]
• Beach Wear Competition (Fire Group)[12]
• Miss Congeniality

At the end of the coronation night of Miss Earth 2022, Mortlock was declared as Miss Earth – Air 2022; while South Korea's Mina Sue Choi was called the winner of Miss Earth 2022.[13][14]