Which ocean is known for having the most islands?

The Pacific Ocean is known for having the most islands. About 25,000 islands are scattered across its enormous basin, far more than in any other ocean.

Many of these islands are grouped into three broad cultural and geographic regions: Micronesia, Melanesia, and Polynesia. They range from tiny coral atolls to large volcanic or continental islands. The Pacific includes island groups such as Hawaii, Fiji, Samoa, the Solomon Islands, the Marshall Islands, and French Polynesia.

The Pacific's island abundance reflects its geology. Subduction zones, volcanic arcs, hotspots, and coral-reef growth have all helped create islands over millions of years. The ocean also contains the Ring of Fire, a belt of intense tectonic and volcanic activity around much of its edge.

Island counts vary because researchers may define and count islands, islets, reefs, and atolls differently. Even with those differences, the Pacific's lead is overwhelming. New Guinea, the Pacific's largest island, is also the world's second-largest island after Greenland.