Famous Irish Myths About the Sea from Due South Clothing

Irish Myths and Legends About The Sea

Ireland has always been shaped by the sea. As an island on the edge of the Atlantic, the ocean isn’t just part of the landscape, it’s woven into our culture, our identity, and our ancient stories. For thousands of years, our ancestors looked out over the waves and saw mystery, adventure, and sometimes, danger.

Some academics suggest that the story of the Sídhe is at the heart of Irish mythology, the mystical race of supernatural beings who dwell in the Otherworld. As Jack Roberts puts it: “The Sídhe are primarily the spirit within the visible world and as such inhabit everything, the earth, the sky and all that is.” They are believed to reside in hidden islands and beneath the waves, just beyond human reach. This week, inspired by The Sacred Mythological Centres of Ireland by Jack Roberts, we’re diving into 9 of Ireland’s most famous myths and legends about the sea. But first…

Who Is the Irish God of the Sea?

If you’ve ever felt the pull of the ocean, you might have been answering the call of Manannán mac Lir, Ireland’s powerful and enigmatic sea god.

Manannán is the ruler of the waves, the guardian of the Otherworld, and the master of mist and illusion. He sails a magical boat called Wave Sweeper that doesn’t need sails or oars, and he carries a cloak that can make him invisible. He’s not just a protector, he’s also a trickster, sometimes helping sailors and sometimes challenging them.

Famous Irish Myths About the Sea

In Irish mythology, the sea is not just a physical body of water but a portal between worlds, a place of mystery, danger, and enchantment. Ireland’s coastline is filled with stories of adventure, lost lands, and magical beings. Some of the most well-known myths involve heroes who take to the sea on incredible voyages.

It’s this same admiration for water, both salt and fresh, that inspired our Sea Collection. You can find our Sea Collection here . And our newest design is from this collection. Uisce Beatha (Water of Life) t-shirt, available in Cool Lavender and Aloe. While some people connect the term “Uisce Beatha” exclusively with Irish whiskey, we love the idea of celebrating the actual life-giving waters around Ireland too.

If you love being in the water or close to the sea you might like Swell Season, inspired by the crashing waves and rolling seas of the west coast of Ireland.

Or if you've a connection to Dublin you'll recognise this iconic landmark.

What Is the Most Famous Irish Myth?

One of the most famous Irish myths tied to the sea is the legend of Tír na nÓg, the Land of Eternal Youth.

1. Tír na nÓg – The Land of Eternal Youth

Oisín, a warrior of the Fianna, falls in love with Niamh Cinn Óir, a beautiful woman from the mystical land of Tír na nÓg, a paradise that lies beyond the western sea. She takes him across the waves on a magical white horse, and they live happily in Tír na nÓg for what feels like only a few years. However, when Oisín longs to return home, he finds that centuries have passed in Ireland. Upon stepping back onto Irish soil, he instantly ages and dies, reminding us of the dangers of longing for what is lost.

2. The Children of Lir – A Tragic Sea Tale

One of the most heart-wrenching Irish legends is that of the Children of Lir. Their jealous stepmother, Aoife, turns them into swans, and they are cursed to spend 300 years on Lough Derravaragh, 300 years on the Sea of Moyle (between Ireland and Scotland), and 300 years on the Atlantic coast. Their story is one of endurance and sorrow, as they endure the harsh storms of the sea until Christianity comes to Ireland and they are finally freed from their curse, only to die as frail humans.

3. The Mythical Island of Hy-Brasil

Hy-Brasil is a legendary island said to lie somewhere off the west coast of Ireland. It was believed to be a land of plenty and wisdom, shrouded in mist, appearing only once every seven years. Many sailors claimed to have seen it, and some even set out to find it, though it was always elusive. This legend has echoes of Tír na nÓg and is similar to the lost city of Atlantis in other traditions.

4. Fionn Mac Cumhaill and the Salmon of Knowledge

Although primarily a land-based hero, Fionn Mac Cumhaill (Finn McCool) had several adventures involving the sea. One legend tells of Fionn and the Isle of Skye, where he battles the sea hag Cailleach Bhéara, who controls the tides. Another story tells of the Salmon of Knowledge, a magical fish found in the River Boyne (which ultimately leads to the sea). By accidentally tasting it while cooking for the druid Finegas, Fionn gains all the wisdom of the world. The Salmon of Knowledge was so ingrained into Irish culture that it featured on our 10p coins, before we converted to the Euro currency.

5. The Selkies – Seal People of Irish Folklore

Although more common in Scottish and Orkney folklore, the Selkies (seal-people) appear in Irish tales as well. These beings could shed their seal skins to become human. In many stories, a fisherman steals a Selkie woman’s skin, forcing her to stay with him as a wife. Though she often bears children, she is forever drawn to the sea and will eventually escape if she finds her hidden seal skin.

6. The Merrows – Irish Mermaids

Irish mermaids, known as Merrows (Muir Óg or Muireadach), were said to be beautiful sea maidens who lured sailors to their doom, but some tales depict them as more benevolent than the mermaids of other traditions. They were believed to wear a red cap (cochaillín draíochta) that allowed them to travel between land and sea. If a man stole the cap, he could prevent a Merrow from returning to the ocean, though she would always long for the sea.

7. The Milesians and the Battle for Ireland

The Milesians, the mythical ancestors of the Irish people, arrived by sea to conquer Ireland from the Tuatha Dé Danann. A great storm was sent against them by the Tuatha Dé Danann’s druids, but their poet Amergin calmed the waves with his song, allowing them to land and claim Ireland. This story reinforces the sea’s role as a gateway between different realms.

8. The Legend of Cúchulainn and the Sea

Cúchulainn, one of Ireland’s greatest warriors, had several encounters with the sea. In one story, he is trained in combat by the warrior-woman Scáthach on the Isle of Skye. He also battles Aife, Scáthach’s rival, and unknowingly fathers a son with her. Years later, he tragically kills his son in single combat, not realising his identity until it’s too late.

9. The Phantom Ship of Dun Laoghaire

Have you heard about the phantom ship seen off the coast of Dun Laoghaire? Witnesses describe a ship appearing in the mist, glowing eerily, before vanishing without a trace. Some believe it to be a doomed vessel trapped in a time loop, forever sailing the Irish Sea.