What Is Thalassophobia?

Written by Matt McMillen
Medically Reviewed by Smitha Bhandari, MD on August 15, 2025
7 min read

Thalassophobia is a fear of large bodies of water, such as oceans, seas, and lakes. Phobias are a type of anxiety disorders.

Thalassophobia is an example of what experts call specific phobias. These irrational and intense fears focus on specific things — called phobic stimuli — that pose no real or immediate danger. It differs from aquaphobia, a fear of water in general.

Examples of other specific phobias include the following:

  • Acrophobia (fear of heights)
  • Arachnophobia (fear of spiders)
  • Aviophobia (fear of flying)

The current edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), which doctors use to describe and diagnose mental illnesses, does not mention thalassophobia specifically. 

Such a phobia would fall under the broader category that the DSM-5 refers to as “natural environment phobias,” which include fear of heights, storms, and water.

What is megalohydrothalassophobia?

Megalohydrothalassophobia is a fear of large underwater creatures or objects rather than a fear of the body of water itself. 

The two phobias are different, but they can be linked.

“Individuals [with thalassophobia] will express worries such as what is beneath the water, darkness under the water, dangers in the water, and being lost,” says Krystal Lewis, PhD, a psychologist in private practice in Bethesda, Maryland, and a board member of the Anxiety and Depression Association of America.

“The experience can feel intense, immediate, and overwhelming, even if the person logically knows they are not in danger,” says Susan Albers, PsyD, a psychologist at the Cleveland Clinic in Cleveland, Ohio. “Patients often describe a sudden wave of fear that takes over both their body and mind.”

You may feel the following physical symptoms:

  • Dizziness
  • Tension in your muscles
  • Rapid heartbeat
  • Shakiness
  • Shortness of breath
  • Stomach discomfort or nausea
  • Sweaty palms
  • Tightness in your chest

The symptoms can be severe. “Patients often describe a ‘fight or flight’ response,” says Brenda Wiederhold, PhD, a psychologist at Scripps Memorial Hospital La Jolla in La Jolla, California. “Some patients describe a full-blown panic attack while others describe ‘strong discomfort.’”

It’s normal to fear large bodies of water sometimes, as when you’re on a boat in a storm.

“[That’s] based on a real and immediate risk,” Albers says. “Your brain is doing its job by trying to protect you from danger.”

Thalassophobia is different. “It’s not just about being afraid during a storm or unsafe condition,” Albers says. “The fear can appear even when there is no real danger at all.”

You can develop thalassophobia in different ways. You may learn it from a traumatic experience, such as nearly drowning in the ocean, Albers says.

“This is an example of classical conditioning, where a specific experience teaches the brain to associate water with fear,” she says.

Thalassophobia can be what Albers calls a learned fear. For example, it may be caused by seeing a traumatic event on the news or in movies or by growing up with someone who had a strong fear of water, she says.

“This kind of learning is called observational learning, and it can shape our emotional responses even without direct experience,” Albers says.

Sometimes thalassophobia comes from a general fear of the unknown or things you can’t control, says David Kupfer, PhD, a psychologist in private practice in Falls Church, Virginia. 

People who grow up in dysfunctional families often cope with or try to feel in control of their situation by avoiding what’s unfamiliar.

For such people, “the ocean might seem like it was potentially full of scary and unpredictable troubles,” Kupfer says.

Your biology may also play a role.

“Some people are just prone to be more anxious, possibly through genetics,” says psychologist Martin Antony, PhD, who chairs the Department of Psychology at Toronto Metropolitan University.

You don’t always need to be near an ocean, lake, or sea to feel fear. Triggers vary from person to person.

“Depending on the intensity of the phobia, individuals may be triggered by thoughts, images, videos, and conversations about open, deep bodies of water,” Lewis says.

The word thalassophobia combines the Greek word thalasso, meaning sea or marine, with the Latin word phobia, meaning fear. The Oxford English Dictionary defines it as "a morbid dread of the sea."

Certain criteria determine whether you are diagnosed with thalassophobia. These criteria include the following:

  • Fear or anxiety triggered by something specific, like an object or situation.
  • That object or situation must nearly always trigger fear or anxiety.
  • You actively avoid the source of your phobia, or you endure it while feeling intense fear and anxiety.
  • The fear or anxiety you feel is out of proportion to any actual danger.
  • Your fear or avoidance lasts for six months or longer.
  • Your fear, anxiety, or avoidance causes stress and affects your daily life, your relationships, your work, or other things.
  • Your fear and anxiety are not the result of another mental disorder.

Antony offers an example of how a phobia might affect your daily life and relationships. Say you have thalassophobia, and your partner wants to go on a scuba diving vacation.

“You won't want to do that, and that will affect your relationship and where you can go on vacation,” Antony says.

But if your fear of large bodies of water does not interfere with your life significantly, he adds: “That's not a phobia. It has to be distressing or impairing.”

Yes. "The good news is that specific phobias (including thalassophobia) are among the most treatable anxiety disorders,” Wiederhold says.

There’s more than one treatment, but your doctor likely will recommend one or more of the following:

Exposure therapy

In this type of therapy, you confront the source of your fear in order to overcome it. Often, this is done gradually. It starts by exposing you to things that only mildly trigger your phobia — for example, a picture of the ocean. It builds up until you face the object of your fear directly. In this therapy, you will learn how to relax and develop breathing techniques to keep you calm.

“This is the gold standard treatment,” says Jaryd Hiser, PhD, a psychologist at the Ohio State University Wexner Medical Center in Columbus, Ohio.

Cognitive behavioral therapy

This is a form of talk therapy. Your therapist helps you to challenge and change the way you think about the source of your fear, such as the ocean. Your fear diminishes, and your confidence builds over the course of therapy until you can control your response to triggers.

Virtual reality therapy

This exposes you through interactive 3D computer simulations in a controlled setting to the source of your phobia. This helps to reduce or overcome your anxiety.

Virtual reality therapy

This exposes you through interactive 3D computer simulations in a controlled setting to the source of your phobia. This helps to reduce or overcome your anxiety.

Medications

Your doctor may prescribe medications to help ease or prevent your thalassophobia symptoms. You will usually take medications for a short term in specific fear-provoking situations. 

The medications include the following:

  • Beta blockers, which help manage anxiety symptoms such as a racing, pounding heart; high blood pressure; and shaking voice and limbs.
  • Benzodiazepines, which are anxiety-reducing sedatives. They can be addictive, so your provider will prescribe them with caution.
  • Antidepressants, which help treat anxiety.

Coping with thalassophobia can be difficult. But there’s plenty you can do to help yourself.

Practice mindfulness techniques

“When fear starts to rise, pause and take a few deep, calming breaths,” Albers says. Then try the “5-4-3-2-1” method: 

  • Name five things you see,
  • Four you can touch,
  • Three you can hear,
  • Two you smell,
  • One you can taste.

“These techniques help shift you out of panic and into the present moment,” says Albers.

Reframe your thoughts

When you have fearful thoughts, you may usually say, “I can’t handle this.” 

Instead, tell yourself, “I am safe,” or “This is uncomfortable, not dangerous.”

Find a support group in person or online

“Talking to others with similar experiences can ease shame and offer encouragement,” Albers says. “Knowing you're not alone is healing.”

Can thalassophobia be fully overcome?

Not always. “I have had numerous patients make it through treatment and get to a point where the phobia no longer impacts their life, but they still may dislike the ocean,” Hiser says.

Albers agrees. “The fear may never fully disappear, and that’s OK,” she says. “Even if the phobia isn’t completely resolved, it can be managed effectively so it no longer interferes with daily life.”

Thalassophobia, a fear of large bodies of water, is what psychologists call a specific phobia. It can cause severe reactions such as panic attacks, even though there is no actual danger.

Thalassophobia and similar phobias can affect your daily life and your relationships. But they are highly treatable with counseling.

What’s the difference between thalassophobia and bathophobia?

Bathophobia is a fear of depths, which could include deep water. Thalassophobia is a fear of large bodies of water.

How rare is thalassophobia?

Experts don’t know how many people have this phobia. But specific phobias are not uncommon. Up to 12.5% of people will have some sort of phobia during their lifetimes.

Why is deep water so scary?

It can be scary for many reasons. If you almost drowned in the ocean, you may develop a phobia of it. Or it can represent the unknown, which can be scary for some people.

What is cymophobia?

Cymophobia is the fear of waves.