Underwater archaeology and the protection of underwater cultural heritage are relatively recent subjects for a number of States – particularly industrialized countries where no specific legislation exists, or legislation favours commercial exploitation of this type of heritage. This article presents an account of the complex situation specific to Brazil, where interests constantly fluctuate. It describes the important role played by archaeologists – often against obstacles and with insufficient financial resources – in working to promote among the public and academia the notion that rules that apply to tangible heritage on land must also apply to heritage under water. This is why the ARCHEMAR Centre was recently created to promote underwater cultural heritage via a museological programme.