The 16-year-old joined her parents, the Earl and Countess of Wessex and her younger brother, James, Viscount Severn, 12, for a beach clean-up at Southsea beach in Portsmouth on Sunday.
The Queen's youngest granddaughter spoke animatedly about starting her A-levels in English, History, Politics and Drama, as she and the Wessexes joined volunteers from the Marine Conservation Society.
WATCH: Edward and Sophie joined by children for rare family outing
Like thousands of pupils across the country, Lady Louise had been preparing for her exams at her school in Ascot before they were cancelled amid the coronavirus pandemic. Instead, GCSE results were based on the grades predicted by schoolteachers.
The young royal's grades were not made public in August and Buckingham Palace said Lady Louise's results were a private matter.
Lady Louise is studying for her A-levels
Lady Louise's mother Sophie previously opened up about her daughter's education in a rare interview with The Sunday Times in June, saying: "She's working hard and will do A-levels. I hope she goes to university. I wouldn't force her, but if she wants to. She's quite clever."
Prince Edward and Sophie's children have mostly grown up out of the public eye and have occasionally attended events, such as Trooping the Colour.
The Wessexes helped to pick up rubbish on Southsea beach
During the beach clean-up on Sunday, Sophie and Lady Louise sounded the alarm about a resurgence in single-use plastic and a lack of official advice on how to dispose of PPE and face masks, which have been found entangled in sea birds and other wildlife.
Teenager Lady Louise worried that much of the progress made in persuading people to use reusable plastic cups had been lost amid the coronavirus pandemic.
"Everything has got worse this year because everyone has gone back to non-reusable, non-recyclable plastic cups," she said.
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