Estrecho del Infiernillo, Marine strait between Tiburon Island and Sonora, Mexico.

Estrecho del Infiernillo is a strait separating Tiburon Island from mainland Sonora. The waterway stretches considerable distances with varying widths that narrow significantly in certain sections.

The Seri (Comcaac) have inhabited the shores of the strait for more than 2,000 years, basing their fishing practices on traditional ecological knowledge. In 1975 President Luis Echeverría declared the strait an exclusive fishing zone for the Seri. On 27 November 2009 the Canal del Infiernillo and the estuaries of Comcaac territory were listed as Ramsar site no. 1891, covering 27,900 hectares.

The Seri (Comcáac) call the strait Xepe Coosot, "narrow sea", or Xepe Heeque, "small sea". Their settlement on its shore is Punta Chueca, Socáaix in the Seri language, inhabited since pre-Hispanic times. For over 2,000 years the Seri have lived here, basing their fishing management on traditional ecological knowledge.

Navigation through the strait requires attention to tidal patterns and strong water currents that shift throughout the day. Visitors planning water activities should time their visits according to tidal conditions and prepare for variable water behavior.

The Ramsar listing of 27 November 2009 covers 27,900 hectares of the Infiernillo channel and the estuaries of Comcaac territory, registered as site no. 1891. Within it live 81 invertebrate species endemic to the Gulf of California, alongside mangroves of three genera and five species of sea turtle.