According to local legend, when Vietnam had just started to develop into a country, they had to fight against invaders. To assist the Vietnamese in defending their country, the gods sent a family of dragons as protectors. This family of dragons began spitting out jewels and jade. These jewels turned into the islands and islets dotting the bay, linking together to form a great wall against the invaders.

Under magic’s, numerous rock mountains abruptly appeared on the sea, ahead of invaders’ ships; the forward ships struck the rocks and each other. After winning the battle, the dragons were interested in peaceful sightseeing of the Earth, and then decided to live in this bay. The place where the mother dragon descended was named Hạ Long, the place where the dragon’s children attended upon their mother was called Bái Tử Long island, and the place where the dragon’s children wriggled their tails violently was called Bạch Long Vỹ island.