70 Ocean Fantasy Writing Prompts: Magical Seas, Sunken Kingdoms & Mythical Creatures
The ocean creates almost limitless possibilities for fantasy. Beyond the shore, familiar maps can give way to unexplored waters, wandering islands, underwater ruins and entire civilisations hidden beneath the waves. A voyage might cross a glittering tropical sea, follow an ancient maritime trade route or descend into depths where sunlight has never reached.
Ocean landscapes can shape cultures just as strongly as forests, mountains or deserts. Kingdoms might depend on fishing and seafaring, powerful cities could control important straits and harbours, and isolated communities may develop their own beliefs about storms, currents and the creatures living below. Mermaids, sea serpents and krakens can exist alongside pirates, merchants, explorers, naval powers and ordinary people whose lives depend on the water.
These 70 ocean fantasy writing prompts include plot prompts, title ideas, opening and closing lines, characters, settings and picture prompts, with inspiration ranging from colourful maritime adventures and romantic voyages to underwater kingdoms, ocean folklore, political fantasy and mysteries from the deep.
Explore more ideas in the Fantasy Writing Hub, or browse the Creative Writing Archive for hundreds more prompts and story ideas across fantasy and beyond.
1. Plot Prompts
The ocean can connect kingdoms just as easily as it separates them. These plot prompts explore voyages, maritime rivalries, strange discoveries and the creatures and civilisations that exist beyond familiar shores.
For centuries, merchant ships have followed the same safe current between two powerful kingdoms. One morning, the current changes direction completely, carrying every vessel towards an unexplored region of the ocean.
A fishing crew accidentally catches a young mermaid in its nets. Before they can release her, she tells them that thousands of people are fleeing an underwater kingdom directly beneath their village.
Two maritime kingdoms are preparing for war over control of a narrow strait when an enormous creature settles on the seabed between them, making it impossible for either navy to pass without disturbing it.
A famous explorer returns after disappearing twenty years earlier. She has not aged, her ship looks newly built and she insists that her voyage lasted only six weeks.
Every spring, a fleet carries pilgrims to a sacred island far beyond the mainland. This year, the ships reach the correct coordinates and find nothing but open water — until bells begin ringing beneath them.
A struggling harbour town becomes unexpectedly wealthy when valuable objects begin washing ashore after every storm. A local diver discovers they are coming from a recently exposed palace on the seabed.
A royal cartographer joins an expedition attempting to map the last uncharted section of the ocean. Each night, someone secretly alters the maps to remove an island the crew is getting steadily closer to.
Pirates capture a merchant vessel carrying what appears to be an ordinary sealed barrel. When they open it, every creature in the surrounding ocean begins following their ship.
A coastal kingdom depends on an ancient agreement with a civilisation living beneath its territorial waters. When the human monarch dies without naming an heir, representatives from below arrive claiming that the treaty gives them the right to choose the next ruler.
Sailors discover a vast floating city built from hundreds of ships permanently lashed together. Its inhabitants claim they have spent generations avoiding land because something follows them whenever they approach a shore.
2. Title Ideas
Ocean fantasy titles can suggest adventure, romance, mystery, danger or the enormous unknown world beneath the surface.
Undertow
Saltborn
The Pearl Crown
Beyond the Blue
Kingdom of Tides
The City Beneath the Waves
Where the Sea Meets the Stars
A Map of Impossible Waters
The Girl Who Bargained with the Kraken
When the Last Ship Returned from the Edge of the World
3. Opening Lines
Ocean fantasy can begin aboard a ship, beneath the waves or at the exact moment something unfamiliar emerges from the sea.
The mermaid climbed aboard shortly before sunrise and asked to speak to the captain.
Nobody aboard the North Star noticed the island until it appeared on the map.
We had been without land for thirty-seven days when the trees appeared beneath the water.
My father taught me never to fear a storm, but he had never seen the sea turn gold.
The king's flagship returned to harbour without a single person aboard.
At low tide, we found a staircase leading down from the beach.
The first warning came when every whale in the bay began swimming towards shore.
I was halfway across the ocean when I discovered that my passenger was supposed to have drowned twelve years ago.
The lighthouse keeper saw the city beneath the waves every night and spent thirty years pretending that he didn't.
On the morning of my coronation, the sea delivered a second crown.
4. Closing Lines
Whether your story ends on the deck of a ship, beside an unfamiliar shore or far beneath the waves, the ocean always leaves somewhere else to explore.
By morning, the island had disappeared behind them again.
She dropped the crown into the deepest part of the sea and watched it vanish.
For the first time in three hundred years, ships crossed the strait without fear.
The harbour bells rang as their sails appeared on the horizon.
He returned the pearl to the water and felt the current change beneath his feet.
They never discovered what lived beneath the ship, only that it followed them home.
She looked back once at the lights glowing below the waves before sailing towards the mainland.
The final blank space on the map was no longer empty.
Somewhere beyond the reef, the kraken sank slowly back into the blue.
At sunset, another ship appeared where the edge of the world was supposed to be.
5. Character Ideas
Ocean fantasy characters can come from above or below the waves, from royal courts and merchant fleets to isolated fishing communities and unexplored waters.
A young navigator who can read currents with extraordinary accuracy but has secretly never learned how to swim.
A mermaid diplomat sent to negotiate the first permanent treaty between an underwater kingdom and the human civilisation occupying the islands above it.
An elderly lighthouse keeper who keeps detailed records of every unusual creature, ship and light he has witnessed during forty years overlooking a dangerous stretch of sea.
A pirate captain who refuses to steal from ordinary merchant ships and instead specialises in recovering treasures from shipwrecks considered impossible to reach.
A royal marine biologist responsible for studying the enormous creatures migrating through the kingdom's waters who discovers that their route forms a deliberate pattern.
A shipwright famous for building vessels capable of surviving almost any storm who is commissioned to construct a ship designed to travel beneath the surface instead.
A pearl diver from a small island community who discovers an underwater road stretching across the seabed towards a place absent from every known map.
The youngest child of a powerful maritime dynasty who is sent to govern a distant harbour city and discovers that its merchants hold more political power than the crown.
A sailor who survived the destruction of an entire expedition and refuses to explain what happened beyond saying that the crew should never have followed the singing.
A deep-sea guardian responsible for protecting an ancient submerged city who begins finding objects from the surface carefully placed outside its gates.
6. Setting Ideas
Ocean fantasy worlds can stretch from sunlit archipelagos and busy ports to midnight depths where entire ecosystems and civilisations exist beyond human knowledge.
A wealthy maritime capital built around an enormous natural harbour, filled with shipyards, markets, warehouses, naval forts and merchant houses competing for control of trade across the known seas.
A warm turquoise archipelago where dozens of inhabited islands are connected by ferries, sailing routes and shallow reefs containing the ruins of an older civilisation.
A vast underwater kingdom built along the walls of an ocean trench, with settlements becoming stranger and more isolated as they descend towards the lightless depths.
A cold northern sea scattered with rocky islands, whale routes and isolated fishing settlements where winter storms can prevent travel for months.
A floating city assembled from ships, platforms and salvaged wreckage, constantly changing shape as new vessels join the community and old sections are dismantled.
A chain of enormous coral cities inhabited by merfolk and other aquatic peoples, connected by underwater roads marked with carved stone pillars and cultivated gardens of kelp.
A dangerous tropical strait where ships must navigate reefs, powerful currents and narrow channels while competing kingdoms maintain fortified ports on either side.
A deep ocean plain containing the remains of a submerged empire, where statues, roads, temples and entire neighbourhoods lie preserved beneath centuries of sediment.
A remote island positioned at the meeting point of several major currents, making its harbour an essential stopping place for explorers, traders, pirates and travellers crossing the ocean.
A region of seemingly endless open water where sailors navigate using stars and currents because compasses fail, maps disagree and islands appear in different places each season.
7. Picture Prompts
Use the ocean scene in front of you as the beginning rather than the whole story. Consider what might exist beyond the horizon, beneath the surface or aboard the vessels moving through the water.
Go Deeper into Ocean Fantasy
The ocean can become one of the largest and most influential parts of a fantasy world. Think beyond what lives beneath the waves and consider how seas shape exploration, trade, politics, culture and the way different civilisations encounter one another.
◆ Build cultures around the sea. Consider how fishing, sailing, shipbuilding, diving and maritime trade influence everyday life. Island communities, great harbour cities and underwater kingdoms might all depend on the same ocean in completely different ways.
◆ Make travelling across the ocean matter. Currents, reefs, storms, seasonal winds and enormous distances can determine where ships travel and which kingdoms become wealthy. Important straits, ports and trade routes can be just as politically valuable as territory on land.
◆ Explore what exists beneath the surface. Create coral cities, submerged ruins, deep-sea settlements and entire aquatic civilisations with their own histories and conflicts. For more inspiration below the waves, explore 70 Underwater Fantasy Writing Prompts.
◆ Fill your seas with stories and creatures. Mermaids, krakens, sea serpents and mysterious deep-water creatures can inspire religions, sailors' superstitions, local legends and dangerous expeditions. You can also explore 100 Fantasy Ocean & Sea Names when naming the waters your characters must cross.
Final Thoughts
Ocean fantasy can take your characters from crowded harbours and colourful island kingdoms to open water, submerged cities and the unexplored depths of the sea. Let the ocean influence how your world travels, trades, survives and understands what might exist beyond the horizon.
Use these 70 Ocean Fantasy Writing Prompts to begin your next maritime adventure, underwater mystery or sea-bound fantasy story, then discover even more inspiration in the Fantasy Writing Hub and Creative Writing Archive.
Choose Your Next Adventure
