The White Circle is a white magical ring that acts as a portal to the Kingdom of Tir Nan Og, where the fairies of Earth were imprisoned.
Season 4The Winx first found the ring exploring a farm from Roxy's childhood. The ring was so important that the Wizards of the Black Circle aimed to get it first before capturing Roxy. The White Circle is the magical opposite of the Black Circle. According to Diana, it is the last hope of earth fairies against the Wizards of Black Circle.
When Roxy finally transformed into a fairy, she fought the wizards greatly but it was not until she used the White Circle (she was scared at first), that the Wizards were defeated in that battle. It opened the portal to Tir Nan Og.
- The White Circle is probably a reference to Fairy Rings, which are naturally occurring rings or arcs of mushrooms. They were associated with lots of legends, and according to English, Scandinavian and Celtic legends they were made by elves or fairies dancing.
- The White Circle was revealed to be absolutely powerful, however it was never revealed if it was equally powerful, less powerful, or more powerful, than the Dragon's Flame.