Email support The first and easiest way to delete your Roblox account is to email its support staff at [email protected] and request that it be deleted. To save time, you should also include your name, ...

Roblox system will constantly monitor the activity of an account and if you haven’t signed in to it in one year or 365 days, Roblox will automatically delete it.

That could be their age. Roblox no longer allows a birthday option for children younger than 5 when setting up an account. And Common Sense Media rates it as safe for users 13+.