Southern Peninsula (Icelandic: Suðurnes, pronounced [ˈsʏːðʏrˌnɛːs] ) is an administrative unit and part of Reykjanesskagi (pronounced [ˈreiːcaˌnɛsˌskaijɪ]), or Reykjanes Peninsula, a region in southwest Iceland. It was named after Reykjanes, the southwestern tip of Reykjanesskagi.
The region has a population of 30,933 (2024) and is one of the more densely populated parts of the island. The administrative centre is Keflavík, which had 7,000 residents when it merged with the nearby town of Njarðvík and Hafnir in 1995 to create Reykjanesbær, which is the largest settlement outside the Greater Reykjavík area; in 2018, the region had a population of 17,805. The region is the location of Keflavík International Airport, the major point of entry for Iceland. Some fishing towns, such as Grindavík, Njarðvík and Sandgerði, are situated on the peninsula.