To help prevent an attack on your town:

• Build lots (about 5-9 harbor turrets should be enough) of protection around your most important goods: fish, building modules, and tools production if the enemy has the chance to attack these targets.
• Try to build as many production chains as possible on your main island where it's easier to protect and will prevent blockades. Without these crucial food and lifestyle products, your population will begin to leave. If your island is very large, this shouldn't be a problem. Since flaks have a large area of influence, 2-3 of them should protect your most important production easily.

When attacking an island, attempt to destroy the most productive energy generating buildings (i.e. dams, solar towers). Going after small energy production buildings such as wind mills is inefficient and doesn't deprive the opponent of major amounts of energy. Turrets and flaks rely on energy, and they will cease to attack if deprived of energy. This translates to the enemy losing a large part of their defenses, giving you a major combat advantage.

Warning: If you are fighting against computer players which have Nuclear Power Plants, do NOT destroy the plant because it will turn into a Nuclear Ruin, so it will make it impossible to defeat that player.

• Moving the necessary production buildings to his main island. This strategy only really works earlier in the game, as later in the game, their main island will not have the necessary fertilities to satisfy his population. Note that doing this will decrease the ecobalance and/or put a greater strain on the island's energy production.
• Reinforcing trade routes with military units and/or transporting the goods in military vehicles. Early in the game, when every player only has one or two trade routes and the militaries are more or less equal in power, blockades will be more difficult to enforce as the opponent might be able to fend off units attacking the trade vehicle. Later in the game, when there are more trade routes, attacking trade ships will be easier as the military will be more spread out defending more trade routes and more territory. Destroying trade ships also forces the opponent to make more trade ships, depriving the opponent of materials and money that might otherwise had gone to other purposes. Also, if enforced for a long period of time, the opponent will not be able to upgrade to the next level of civilization, and the respective buildings that come with it. This will give you an advantage over the opponent as you are more advanced, have more income, and possess buildings your opponent doesn't.

The blockade is an offensive tactic, and you will need to be able to build military ships quickly and have success with destroying the opponent’s ships or else you will be wasting time, money, and resources.

	Deep Ocean Expansion Required! You require the Deep Ocean expansion to unlock this content.

See also Island Shares and Hostile Takeovers.

A hostile takeover constitutes buying shares in an island until you are able to outright buy the island. You will not be able to purchase shares until you reach the third tier of civilation. Once you purchase a share, you will not be able to purchase another for another ten minutes. When you own 60% or more of the shares in an island, you can purchase the island. To purchase shares, click on the island’s warehouse/port authority, and in the top right of the screen will be a window where you can buy the shares. You start with already having purchased three shares on your first warehouse.

Preventing a hostile takeover:

• Purchase shares on your own island. However, this will NOT prevent a takeover. The opponent will still be able to purchase shares you’ve already bought, albiet at a higher price.
• Purchase shares on one of your opponent's islands. This will force the opponent to buy back that share rather than buying shares on your islands if they want to avoid losing their island to a hostile takeover.