Llyn Llydaw lake is in the Snowdonia National Park, in North Wales. It is only about ten miles from Llyn Ogwen. another of the purative Excalibur lakes.
Local legend believes that Sir Bedivere threw the Excalibur into this lake, Llyn Llydaw, below Mount Snowdon. Some legends also say Llyn Llydaw, is the one over which the wounded Arthur sailed to the Isle of Avalon. The lake is very remote though and inaccessible.
Whether Sir Bedivere could have made has way to such a remote lake is to be considered, but maybe that was the charm of the place for the Lady of Lake if she in fact lived in Llyn Llydaw.