After her spouse died, Augusta was the presumptive regent of Great Britain in the event of a regency, until her son reached majority in 1756.

In 1736, it was proposed that she marry 29-year-old Frederick, Prince of Wales, eldest son of George II of Great Britain and his queen consort Caroline of Ansbach.

[3] Augusta did not speak French or English, and it was suggested that she be given lessons before the wedding, but her mother did not consider it necessary, as the British royal family were from Germany.

[4] Augusta of Saxe-Gotha left Hellevoetsluis 17 April 1736 and arrived at Greenwich on the royal yacht William and Mary on the 25th, where she was welcomed by her groom.

When she was introduced to the royal family, she made a favourable impression on the king and queen by throwing herself on the floor before them in a gesture of respect.

During the first year of marriage, Augusta could be seen playing with her doll in the windows of her residence, until her sister-in-law, Princess Caroline, told her to stop.

[2] The delivery was traumatic: St James Palace was not ready to receive them, no bed was prepared, no sheets could be found, and Augusta was forced to give birth on a tablecloth.

[2] Queen Caroline once said of her daughter-in-law and the inconveniences she had inflicted on her: "Poor creature, were she to spit in my face, I should only pity her for being under such a fool's direction, and wipe it off.

It was six in the morning before her attendants could persuade her to retire to bed; but she arose again at eight, and then, with less thought for her grief than anxiety for the honour of him whose death was the cause of it, she proceeded to the Prince's room, and burned the whole of his private papers.

[8] During the remaining years of the reign of George II, Augusta chose to live in seclusion with her children, devoting herself to their care.

[9] When Charlotte turned to her German companions for friends, she was criticised by Augusta for keeping favourites, notably her close confidant Juliane von Schwellenberg.

He was the butt for everybody's abuse; for Wilkes, for Churchill's slashing satire, for the hooting of the mob who roasted his booth, his emblem, in a thousand bonfires; that hated him because he was a favourite and a Scotsman, calling him Mortimer, Lothario, and I know not what names, and accusing his royal mistress of all kinds of names – the grave, lean, demure, elderly woman, who, I dare say, was quite as good as her neighbours.

[8] When the King had a first, temporary, bout of mental illness in 1765, Augusta and Lord Bute kept Queen Charlotte unaware of the situation.

[10] In the end, Louise von Plessen was not reinstated, and Augusta apparently asked Caroline Matilda not to press the matter and to show more affection to Christian.

In particular these concerned the mental state of her spouse as well as the fall of prime minister Count Johann Hartwig Ernst von Bernstorff, in which Caroline Matilda was rumoured to have participated.

[8] When Augusta visited her eldest daughter in Brunswick that year, she also took the opportunity to see Caroline Matilda, who received her in breeches, which at that time was regarded as scandalous.

Several places in British America were named in her honour: Michelle Fairley portrayed a fictionalized version of Augusta in Queen Charlotte: A Bridgerton Story (2023).