Mactan is a densely populated island located a few kilometers east of Cebu Island in the Philippines. The island is part of Cebu province and it is divided into the city of Lapu-Lapu and the municipality of Cordova. The island is separated from Cebu by the Mactan Channel which is presently crossed by three bridges: the Cebu–Cordova Link Expressway (CCLEX), the Mactan–Mandaue Bridge, and the Marcelo Fernan Bridge. The island covers some 65 square kilometres (25 sq mi) and has a population of 527,071 as of 2020, making it the nation's most densely populated island. Along with Olango Island Group, the isles are administered by a city and a municipality covering 75.25 square kilometres (29.05 sq mi).

Cebu, officially the Province of Cebu, is a province of the Philippines located in the Central Visayas (Region VII) region, and consists of a main island and 167 surrounding islands and islets. The coastal zone of Cebu is identified as a site of highest marine biodiversity importance in the Coral Triangle.