Roblox lets eligible users join one another in games, but the available options depend on age, privacy controls and the game. Parents can reduce unwanted contact by reviewing who may join the child and who the child may join.
This is separate from chat. A person may be able to enter the same server even when direct messages are limited.
Review visibility and joining controls
Open the linked parent account, select the child and check Privacy or Communication settings. Look for controls about who can join the child in experiences.
Choose the narrowest setting that still supports the child's normal play. For a younger child, limiting joins to known connections can reduce random follow attempts.
Check connections and private servers
The join setting works alongside the child's connections. Remove or block accounts that should no longer have contact rather than relying on one global control.
Private-server owners decide who receives access, and invite links can be forwarded. Regenerate a link or change server permissions when an unwanted player has obtained it.
Teach the child what to do in a server
Controls cannot predict every social situation. The child should know how to leave, block and report somebody who repeatedly follows them or pressures them to join another place.
Ask for the exact username, not only the display name. Several accounts can use the same display name, while the @username identifies the account involved.