The Imperial Navy is the aquatic fighting force for the Empires of Cyrodiil. The navy has been tasked with anything from hunting down pirates to fighting wars and even invading the continent of Akavir. They are known to have existed from the First Era through to the Third and later Fourth Era.
The Imperial Navy has seen many conflicts over the thousand years its been around. It is charged with keeping peace throughout Tamriel by stopping pirates and even going to war if necessary with other nations if necessary.
In 1E 1033 the Imperial Navy was tasked with hunting down a Bramman. Bramman was an Argonian pirate who constantly harassed and raided ships in the Topal Bay. Eventually, Empress Hestra took notice of this. She sent ships from the Imperial Navy to destroy the pirates ship, kill his crew, and execute Bramman himself. Ships chased him through Black Marsh after failing to kill him in the Topal Bay. They eventually cornered him near what would become the City of Blackrose and they executed him.
When Tiber Septim was still trying to conquer all of Tamriel the Imperial Navy undoubtedly saw combat all across Tamriel. However, the only known fighting it did was that of the New West Navy in Hammerfell.
This faction of the navy had two known leaders, the first being Vasi Hadrach until sometime in the 9th century of the second era when he was assassinated. The second was one of Septims potentates, Amiel Richton. Under Amiel the navy went on to win the Battle of Hunding Bay where he defeated the last High King of Hammerfell, Thassad II. After this battle Stros M'Kai was conquered, which was the last place in Tamriel unconquered by the Empire.
This navy consisted of mostly Colovian Nobility. This navy also has pictures drawn of it, giving us a good image at what the Imperial Navy might have had for ships during the Tiber Wars.
The navy played a major role in the Empire's assault on Akavir from around 3E 271 to 3E 290. In the early years of the 270's during the Third Era, the Emperor, Uriel Septim V, began planning an invasion of Akavir and several islands in between Tamriel and the continent. It was decided that the current size of the Imperial Navy was not large enough to carry out this invasion, so the Emperor ordered that new ships be built. Thus the Far East Fleet was created. It was said to be so large that the new fleet nearly doubled the current size of the navy. The fleet is known to have been able to carry at least two Legions with large amounts of supplies for a long voyage.
The fleet was originally made to invade Akavir, but it had other objectives as well. Before it could sail to Akavir the fleet needed to conquer the islands of Roscrea and Esroniet.  These islands were wealthy trade islands that the Imperial Navy would use as military ports to sail to Akavir. Once the islands had been taken the fleet was loaded up with Imperial Legion soldiers and sent off to Akavir.
When the fleet arrived they did no fighting. The Tsaesci had no navy for the Imperial Navy to face, so they simply delivered off their troops. Many sailed off to preform supply runs across the ocean and bring more legions and settlers over for the invasion. However constant storms slowed and eventually halted all sailing across the ocean until the Emperor authorized the use of battlemages to accompany the fleet to stop the storms.  Eventually disaster struck the legions in Akavir and almost every soldier was killed, along with the Emperor. Much of the fleet was also destroyed in this failed conquest and never has the Imperial Navy rebuilt the New West Navy.
The Imperial Navy also fought in the Great War, where they had naval clashes on Lake Rumare with the Aldmeri Dominion Navy. These naval clashes ultimately ended in failure, as the Imperial City fell in the year 4E 174 on the 12th of Second Seed to the supieror force of the Aldmeri Dominion.
- Bountiful Mara: A ship mentioned in The Elder Scrolls Online which had a member named Kuralit.
- The Katariah: The Emperor's personal ship in the year 4E 201. The ship is likely named after Empress Katariah, who ruled during the third era. The ship can be found during the events of The Elder Scrolls V: Skyrim.
The following navies are, or have been historically, part of the Imperial Navy: