Every island has a set of Fertilities and Raw Material Deposits, as well as coastlines for Fisheries and other coastal buildings, but not every island contains River slots for buildings which need to be placed over a River, or Water Dam slots which is required to plant a Hydroelectric Dam on the island.
Islands come in three sizes: small, medium and large. Generally it is worth placing Population settlements on large islands and Production plants on smaller islands. Fertility is not percievably affected by the size of an island, however especially in Single Missions and Global Events you can count on smaller islands having few (1-2) and large islands having more (3-4) fertilities.
Islands in Continuous Games may also have positive or negative Environmental conditions existing on them prior to colonization, such as the Automated Sewage Plant or the Damaged Nuclear Reactor,which give them a starting bonus of +150 or reduction of -200 Ecobalance, respectively.
Like in Anno 1404, island ownership is not mutual and it is possible for both players and Computer Players to settle islands which have already been settled by someone else. Take note however, that NPCs will react differently to having another settlement colonized on their islands.
Note: Settled Islands my be renamed by clicking on the island's name on the main Warehouse panel in the top-right corner of the screen.
A unique feature to Anno 2070 are islands that exist under the sea, which are called Underwater Plateaus. Settling on an underwater plateau by building a Deep Sea Warehouse requires Submarines and access to Tech production. Furthermore, buildings constructed underwater require only the basic materials: Building Modules and Tools. Some of the Deep Ocean underwater buildings also cost carbon.
Underwater Plateaus may also contain Black Smokers, see Fertility.
Utilizing the limited space of underwater plateaus requires careful micro-management, even more so because underwater buildings tend to have higher upkeep costs than their land-based counterparts.