How to sail across open seas in Civilization 7

In Civilization 7, expanding your empire isn’t just about conquering land — it’s also about mastering the seas. However, deep ocean travel isn’t available from the start, and even when you gain access, the risks are high. To explore new lands safely, you must conduct key research and plan your routes carefully.

This guide explains you to unlock ocean travel in the game, avoid ship damage, and navigate the seas effectively.

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How to navigate open seas in Civilization 7

Unlock ocean travel

At the start of Civilization 7, during the Antiquity age, all ships and units are restricted to coastal waters. While they can navigate along shorelines, they cannot enter the deep ocean, which remains completely inaccessible. This limitation exists because the early game focuses on developing your civilization on its starting continent rather than immediately reaching distant lands.

You need shipbuilding to start exploring the open ocean (Image via 2K Games)

To move beyond coastal waters, you must advance to the Exploration age. You will enter this phase once you have collected enough age progression points in the Antiquity age. These are earned through various in-game actions such as technological advancements, cultural developments, military conquests, and economic growth.

As soon as the Exploration age begins, you will gain access to military naval units, such as the fleet commander, which can enter the open ocean.

Merchants need cartography to sail across the open ocean (Image via 2K Games)

However, non-military units, like scouts and merchants, still cannot cross deep waters at this point. To allow them access, you must first research Cartography.

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Surviving the open ocean

Once you are in the open ocean, you have to deal with ocean damage. Any ship that ends its turn on an open ocean tile will lose HP. The exact damage varies depending on the unit, but early ships typically take 14-20 points of damage per turn.

Fleet commander in Civilization 7 (Image via 2K Games)

At the start of the Exploration age, the only way to prevent a ship from sinking is to return to coastal waters, where it will heal at the end of each turn. Moving carefully between coastal tiles while minimizing time spent in deep waters is key to keeping your fleet intact.

To eliminate ocean damage, you must research Shipbuilding. Once unlocked, your ships can cross the ocean freely without taking damage. However, civilian units will still be vulnerable. To allow all units to travel safely, research Shipbuilding II, which extends this protection to non-military ships.

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If you're in a hurry, you can attempt ocean crossings before researching the necessary technologies — but this is a gamble. Some units may reach land in time, while others may not survive. A safer approach is to unlock Cartography, Shipbuilding, and Shipbuilding II as early as possible to ensure your fleet can travel freely and expand your civilization to new continents without setbacks.

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Check out our other Civilization 7 guides:

• All map types in Civilization 7
• All Trophies in Civilization 7 and how to unlock them
• What are Celebrations in Civilization 7?
• How long does it take to beat Civilization 7?
• How to win an Economic Victory in Civilization 7