From Wikipedia,

Seasteading is the concept of creating permanent dwellings at sea, called seasteads, outside the territory claimed by any government. The term is a blend of sea and homesteading.

Proponents say seasteads can "provide the means for rapid innovation in voluntary governance and reverse environmental damage to our oceans ... and foster entrepreneurship." Some critics fear seasteads are designed more as a refuge for the wealthy to avoid taxes or other obligations.

No one has yet created a structure on the high seas that has been recognized as a sovereign state. Proposed structures have included modified cruise ships, refitted oil platforms, and custom-built floating islands.

As an intermediate step, the Seasteading Institute has promoted cooperation with an existing nation on prototype floating islands with legal semi-autonomy within the nation's protected territorial waters. On January 13, 2017, the Seasteading Institute signed a memorandum of understanding (MOU) with French Polynesia to create the first semi-autonomous "seazone" for a prototype, but later that year political changes driven by the French Polynesia presidential election led to the indefinite postponement of the project. French Polynesia formally backed out of the project and permanently cut ties with Seasteading on March 14, 2018.

The first single-family seastead was launched near Phuket, Thailand by Ocean Builders. Two months later, the Thai Navy claimed the seastead was a threat to Thai sovereignty. As of 2019, Ocean Builders says it will be building again in Panama, with the support of government officials.