The first flotation tank was developed in 1954 by the American neurophysiologist Professor Dr. John C. Lilly while working at the National Institutes of Mental Health (NIMH) in Bethesda, Maryland. Together with his associate Dr. Jay Shirley, Dr. Lilly became intrigued by the question of the origins of conscious activity within the brain. The question was whether the brain needed external stimuli to keep its conscious state going.

Lilly and his associate set to work trying to devise a system that would restrict environmental stimulation as much as was practical and feasible. Lilly's first tank was one in which the floater was suspended upright, entirely underwater, head completely covered by an underwater breathing apparatus and mask. Tanks of those days would be very intimidating to the average person. 

Other refinements such as water heaters with thermostats sensitive enough to keep the water at perfect temperature, and air pump to keep the air in the tank fresh, and a water filter for the reuse of the Epsom salts were added over the years. By the early 1970s, Lilly had perfected the flotation tank in much the design used today. The Flotation tank which the neurophysiologist Dr. Lilly designed has not only been used by neurologists at university medical faculties. Scientists in other fields of research have shown increasing interest in the flotation tank and its effects on the human body and mind.

In 1982, International REST Investigators Society (IRIS) was founded in order to give the increased number of REST researchers a platform to share their research findings. For several years float tanks were solely used by researchers in university laboratories or by private individuals.

Lilly wanted to bring floating to the general public, and he partnered with Glen and Lee Perry to design a float tank that would allow people to bring home the benefits he had found reported in his studies.

Glen and Lee Perry designed the tank to free the person in the float from a restricting diving suit, uncomfortable face mask, and an ominous flotation chamber. They created a light-proof enclosure, and opted for flotation instead of submersion. In order to make the flotation easier for people, they added one important addition to the mix. The addition? Salt. Not just any old table salt (though they tried that, and were displeased with the sting), Epsom salt, a much more skin-friendly salt that has long been recognized for its health benefits.

This salt water, filled nearly to the point of saturation, created an extremely buoyant environment, making the act of floating entirely automatic, essentially counteracting the “sense” of gravity and letting the body relax more than ever before. This basic recipe of Epsom salt and water is still used in float tanks today, though now they come in all shapes and sizes. They all focus on creating a soundproof, lightproof, ultra-buoyant environment where people can enter and experience a complete blackout of their external senses.

In 1983 floating increased in popularity as more became known about it's effects. Today, floating is growing in popularity with over 250 centers all over the world. Flotation tanks can be found in health spas, hospitals, fitness centers, professional sport centers, bio-fitness institutes, and are used for "Super learning" courses by universities.