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Open Ocean, or Ocean, is a base terrain within the Marine biome in Civilization VII and its expansions. It appears as deep blue water regions beyond Coastal tiles, forming vast expanses that separate landmasses and continents.
Mechanics[]
Unlike land, Open Ocean tiles cannot be improved or developed, and they do not contain any resources. Their primary function is to serve as barriers and transit zones between continents. Access to these tiles evolves throughout the game as civilizations progress technologically:
- Antiquity Age – Open Ocean tiles are completely inaccessible, preventing early exploration of distant continents.
- Exploration Age – Naval units can enter the Open Ocean but suffer attrition damage if they end their turn there. Advancing in the technology tree removes this penalty, while also increasing movement speed and allowing non-naval units to traverse these tiles.
- Modern Age – All units can freely traverse the Open Ocean without restrictions.
At the top and bottom of the map, Open Ocean is bordered by Ice Tiles, representing the North and South Poles. These tiles are completely impassable, forming the natural boundaries of the world. However, the horizontal edges of the map are connected, allowing ships to cross from one side to the other, effectively simulating a round world.
Strategy[]
As mentioned before, Open Ocean tiles are completely inaccessible during the Antiquity Age, so they only become a factor from the Exploration Age onward. At this stage, civilizations must consider how to approach oceanic expansion and security.
Since Open Ocean provides no direct benefits, players should avoid settling on small islands surrounded by vast ocean tiles, as they often lack the resources needed for efficient development. However, strategically placed island 
Settlements can serve as military forts — safe havens for naval forces that provide control over key waterways and act as a buffer to protect mainland territories.
This becomes particularly crucial during the Exploration Age, when civilizations seek to cross the ocean to settle on Distant Lands. The resulting naval conflicts can turn the Open Ocean into a wide battleground, making coastal Settlements vulnerable if left unguarded. Establishing a strong navy and securing key ocean passages can provide a strategic advantage.
If you aim to progress in the economic and militaristic Legacy Paths of the Exploration Age, prioritizing research into Open Ocean navigation from the beginning is highly advisable. Gaining early access allows you to settle on distant lands before rival civilizations claim them. Additionally, naval dominance grants control over critical ocean routes, enabling you to monitor opponents, block their Settlers, and even launch preemptive strikes against unprotected 
Cities. This can significantly accelerate your expansion and establish an early power advantage over other civilizations.
Gallery[]
.png "Open Ocean in-game (Civ7).png (1.33 MB)")
See also[]
- (Open) Ocean in other games
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