The contact lens is floating in my eye, why is it so?

Contact lenses are hydrophilic discs that do not even touch the surface of the eyes. They float on a layer of tears that covers the cornea. Thus, contact lenses are actually “designed” to float in your eyes. Minor contact lens movement & floating should not warrant the concern unless you find your contact lenses conflicting with your vision.
a. Blinking:
Since your eyes draw its oxygen from the environment, soft contact lenses are made to float. If they were made the other way, oxygen transmission would be harmfully compromised. Blinking dislodge contact lenses to a few millimeters, but they are relocated within a fraction of second. Every time you blink your eyes, a fresh oxygen-laden supply of tear film bathes contact lenses to keep your eyes moist & hydrated.
b. Tear Film:
Tear film facilitates contact lens floating. When the tear-chemistry is disturbed, contact lens floating is compromised. When contact lenses cease to float healthily, eyes begin to itch or inflammation is observed. Lubricating drops may provide relief from discomfort.
c. Improper Fitting:
Contact lenses with an average base curve of 8.6mm tend to fit most of the people. However, people with special needs, might need to meet the ophthalmologist before getting themselves a pair of circle contacts. Contact lenses that are too loose may fall off or get trapped in the eye lid - yet you don’t need to worry. Contact lenses can never go lost in your eyes. Similarly, contact lenses with too tight base curve can block oxygen permeation.
Contact lenses are designed to shift to a few millimeters, but they keep coming back to the right position over pupil without even letting you realize. Contact lens sliding must not interfere with your vision but depending on the design contact lens movement can sometimes bother with the vision. For instance crazy lenses with opaque design. Floating of contact lenses therefore, must go unnoticed. If it is bothersome and persistent with different models of contact lenses, get yourself checked by an eye professional.