The Pirates of Dark Water is a fantasy animated series produced by Hanna-Barbera and Turner Entertainment in the early 1990s. The series followed a group of adventurers on a quest to collect the Thirteen Treasures of Rule, which possessed the combined power to stop an evil substance known as "Dark Water" from consuming the alien world of Mer.

The show first premiered in syndication in early 1991 as a five-part mini-series titled Dark Water. Following a number of animation tweaks and other changes by Hanna-Barbera, those episodes were rebroadcast later in 1991 as the first five episodes of the regular series. Most notably, the original mini-series featured the voice of Roddy McDowall as Niddler, whereas in the revised version, the character was voiced by Frank Welker. The first season aired on ABC, while the second season aired in syndication as part of The Funtastic World of Hanna-Barbera.

Due to expensive production costs and failing to meet the airdates, the series was never completed, ending abruptly after 21 episodes with only eight of the thirteen Treasures collected.

The show has not yet been officially released on DVD, although select episodes of the show were released on VHS in NTSC format. Many of the show's fans have been very vocal in their requests for a complete series DVD set, as well as the mini-series version, though as of 2007, an official release is still unavailable.

When Ren, a young son of a lighthouse keeper, rescues a stranger foundering in the rocks near his home, he learns the man was an aide to his true father, a great king. Ren is given a magic compass crystal that guides him to a dragon who shows him that the only way to claim his heritage is to find the Thirteen Treasures of Rule. Unfortunately, a pirate ship captained by the evil Bloth is also aware of this treasure and is relentlessly pursuing Ren for it. On his side, Ren soon acquires companions like Ioz the Pirate, Tula the Eco-Mage and Nibbler the Monkey Bird who help him in his quest. That quest becomes all the more urgent when Ren learns that the Dark Water, a carnivorous form of water that consumes anything it snares, threatens to envelope and destroy his world and only the treasures he seeks can stop it. Written by Kenneth Chisholm

Mer is another world. Most of the planet's surface is water, "The Twenty Seas" where there are creatures such as: Monkey-Birds and the Levithan. On Mer, Octopon was once a great city ruled by Primus, Primus was captured by the evil pirate Bloth, captain of the most feared pirate ship "Maelstrom" (who is after the Thirteen Treasures of Rule) and wiped out Primus's fleet, killed every heir to the throne of Octopon. But several of Primus's captains escaped with the treasures. 17 years later, Ren, a young teenager raised by a lighthouse keeper, learns he is the son of Primus and heir to the throne of Octopon. Joined by his companions: Niddler, loyal and cowardly Monkey-Bird, Ioz, a former pirate, Tula, a young ecomancer with the power to control nature and Zoolie, also a former pirate. Ren and his companions embarks on a quest as they travel across Mer in search of the Thirteen Treasures of Rule, where Bloth bids to take possession of the Thirteen Treasures of Rule and control "The Dark Water" tar-like water which swallow anything in it's path and engulf every island on Mer and destroy the world. By finding the treasures, only Ren and his companions can save the world from destruction. Written by Daniel Williamson