Thalassaphobia, while not an officially recognised one under some medical manuals, comes under the umbrella heading of an environmental phobias. For all that it isn’t one of the better known or more common phobias, it can result in extreme reactions among case studies of sufferers. Flying over the ocean can trigger an episode, even just associative words can elicit a response.
Separate to Aquaphobia, while related and in some cases overlapping this isn’t a fear of the water itself. Someone with Thalassophobia isn’t afraid of drowning, they’re afraid of something unseen in the waters getting them.

Clear water isn’t what “gets” you, with Thalassophobia. It’s a phobia about what you can’t see. Dark and murky waters are where this fear breeds, and worst of all in immensity. That as you go deeper, the light stops piercing the water. To go deeper still, the light just stops even under the noonday sun. What’s under there, where light is no longer natural, can really drive the imagination into a gibbering wreck.
Speilberg’s ‘Jaws’ is one of the most successful Summer blockbusters of all time, itself being THE first of these tentpole studio movies as we know them. This common phobia play of a giant hungry primeval throwback that can strike when we’re out of our element certainly struck a chord.
It’s people who grew up watching Jaws who will resonate immediately and strongly with this specific fear. The internet is full of think pieces, usually penned around anniversaries of the movie, where people admit their strange reactions after growing up watching Jaws. People who stopped swimming in the ocean and lakes, unable to handle the thought of what could be there with them in an element humans simply aren’t suited to. People who stopped taking baths, even, sticking to showers and basin washes they were so overwhelmed.
Now I mention it, I have a childhood story like this myself… I had a toy shark I would play with in the bath, not a cartoon-y one either. One night, being a council estate kid in a home with an electric meter, the power suddenly failed. I was in the bath, in the dark, and somewhere in there with me was the toy shark.
I screamed the house down!

While hardly the first phobia to spring to mind, this one is a powerful one. Just lurking deep in the back of your brain, waiting to swallow you up. It appears to be one of the phobias Dr. Franklin R Schneier refers to in his book ‘Prepared Fears’ as a “hardwired” fear that can form with as little as one exposure, something so primal that it isn’t a conditioned response and is something we’re born prepared to fear as a survival response.
I’ll leave you with HP Lovecraft himself on the oceans:
“But more wonderful than the lore of old men and the lore of books is the secret lore of ocean. Blue, green, grey, white, or black; smooth, ruffled, or mountainous; that ocean is not silent. All my days have I watched it and listened to it, and I know it well. At first it told to me only the plain little tales of calm beaches and near ports, but with the years it grew more friendly and spoke of other things; of things more strange and more distant in space and in time. Sometimes at twilight the grey vapours of the horizon have parted to grant me glimpses of the ways beyond; and sometimes at night the deep waters of the sea have grown clear and phosphorescent, to grant me glimpses of the ways beneath. And these glimpses have been as often of the ways that were and the ways that might be, as of the ways that are; for ocean is more ancient than the mountains, and freighted with the memories and the dreams of Time.” – HP Lovecraft
Read the previous edition of “Defining Fear” here!
If you suffer from Thalassophobia, we have a suggested resource which may help you: https://www.choosingtherapy.com/thalassophobia/
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Luke Greensmith is an Editor at the Grimoire of Horror and an active folklorist as well as working in film across a few roles. While this can cover quite a wide range of things, he’s a dedicated horror fan at heart and pretty involved with horror communities both online and local to him. You can find their folklore work on the Ghost Story Guys Podcast, their own LukeLore podcast, and accompanying the artist Wanda Fraser’s Dark Arts series as well as on the Grimoire of Horror itself.