Historically, island countries have been less prone to political instability than their continental counterparts. The percentage of island countries that are democratic is higher than that of continental countries. 
Island countries have often been the basis of maritime conquest and historical rivalry between other countries. Island countries are more susceptible to attack by large, continental countries due to their size and dependence on sea and air lines of communication. Many island countries are also vulnerable to predation by mercenaries and other foreign invaders, although their isolation also makes them a difficult target.
Many island countries rely heavily on fish for their main supply of food. Some are turning to renewable energy—such as wind power, hydropower, geothermal power and biodiesel from copra oil—to defend against potential rises in oil prices.
Some island countries are more affected than other countries by climate change, which produces problems such as reduced land use, water scarcity and sometimes even resettlement issues. Some low-lying island countries are slowly being submerged by the rising water levels of the Pacific Ocean. Climate change also impacts island countries by causing natural disasters such as tropical cyclones, hurricanes, flash floods and drought. In 2011, the Center for Climate Change Law (CCCL) held a conference attended by 272 registrants from 39 island nations titled Legal Issues for Threatened Island Nations.
Many island countries rely heavily on imports and are greatly affected by changes in the global economy. Due to the nature of island countries their economies are often characterised by being smaller, relatively isolated from world trade and economy, more vulnerable to shipping costs, and more likely to suffer environmental damage to infrastructure; exceptions include Japan and the United Kingdom. The dominant industry for many island countries is tourism.
Some island countries are centred on one or two major islands, such as the United Kingdom, Trinidad and Tobago, New Zealand, Cuba, Bahrain, Singapore, Iceland, Malta, and Taiwan. Others are spread out over hundreds or thousands of smaller islands, such as Indonesia, the Philippines, The Bahamas, Seychelles, and the Maldives. Some island countries share one or more of their islands with other countries, such as the United Kingdom and Ireland; Haiti and the Dominican Republic; and Indonesia, which shares islands with Papua New Guinea, Brunei, East Timor, and Malaysia. Bahrain, Singapore and the United Kingdom have fixed links such as bridges and tunnels to the continental landmass: Bahrain is linked to Saudi Arabia by the King Fahd Causeway, Singapore to Malaysia by the Johor-Singapore Causeway and Second Link, and the United Kingdom has a railway connection to France through the Channel Tunnel.
Geographically, the country of Australia is considered a continental landmass rather than an island, covering the largest landmass of the Australian continent. In the past, however, it was considered an island country for tourism purposes (among others) and is sometimes referred to as such.