Although there are many species of jellyfish and venomous marine animals, the first aid and medical treatment of their bites and stings can be grouped simply. Some of the more important situations causing marine envenomation – that is, jellyfish stings and envenomation from sea animals – are discussed in this article. It highlights common potential marine risks to travellers while they are overseas or travelling around Australia, and details first aid and medical treatment of these animal’s bites and stings. A comprehensive review of the subject is beyond the scope of this article.