Hydrophis zweifeli is a species of snakes found from New Guinea to Australia (Northern Territory and Queensland).

DNA test have shown they are not related to Hydrophis schistosus.

[2] Hydrophis zweifeli are commonly known as the Sepik beaked sea snake or Zweifel's beaked sea snake.

Hydrophis zweifeli is a highly venomous species of sea snake.

[3] Studied Hydrophis zweifeli have been near the mouth of Sepik River of New Guinea.