Planet Wellbeing - using extended reality to improve mental health and reduce loneliness. One in 15 people aged 50+ are often lonely, rising to one in three for those who are widowed, and one in four for those in poor health. Loneliness and social isolation have numerous health consequences including 26% increased mortality likelihood and more than doubling the risk of developing dementia. Lonely individuals are more prone to both depression and suicide. Many older people are unable to maintain rewarding in-person connections due to restricted physical mobility or mental health issues such as anxiety or depression. For this group digital engagement via rich, multiuser extended reality games may provide opportunities for deep social engagement and significant agency; however, these games are often not designed for older people. We previously developed a user interface that captured older-people's real-world physical actions and used them to navigate a rich virtual world. We showed that older users were able to interact and perform complex activities in the virtual world, with natural movements giving them a strong sense of presence.We will develop Planet WellBeing - a virtual world to allow people to use natural physical movements to control their avatar performing fun and engaging activities with friends and family and/or strangers in a virtual environment. These activities could include exploring on foot or in vehicles, dancing, games, interacting with robot animals, etc. As well as non-moderated use, some sessions will be led by expert-practitioners/therapists who will facilitate rich social interactions and conversations that participants may find difficult in real-world settings. We suggest the rich social engagement within this world will benefit users' mental wellbeing and reduce feelings of loneliness. We will : -Co design the physical interfaces and virtual scenarios with older people -Develop Planet WellBeing - an age-appropriate virtual environment ; suitable for at-home use by older users. -Recruit between 15-25 users as a minimum with potential to increase to 50, at home for 12 week period, providing immersive hardware. -Assess mental health as well as loneliness, usability, engagement, physical and quality of life outcomes at the start end, and at points throughout the 12 weeks. This work will include demonstrator and trials for later large scale study and eventual system rollout. The project will be led by immersive specialists PixelMill , with the support of the Advanced Wellbeing Research Centre (AWRC) at Sheffield Hallam University, Shapemaster Global and Age UK Sheffield.