* Caerphilly Castle: This medieval castle served as the primary location for Camelot.
* Pembrokeshire Coast National Park: Coastal scenes, including the famous "Merlin's Cave" were filmed here.
* Snowdonia National Park: The dramatic mountain landscapes of Snowdonia were used for various outdoor scenes.
* Margam Country Park: This park, with its stately home and gardens, was used for various scenes, including the King's court.
* Other locations: Various other locations in Wales were used for specific scenes, including forests, beaches, and villages.
While the series is primarily set in Britain, some scenes were filmed in France for locations like the kingdom of Cenred.
Therefore, the main filming locations for "Merlin" were Wales and France.