Chi Aquarii, Latinized from χ Aquarii, is the Bayer designation of a star in the equatorial constellation of Aquarius. The distance to this star, based upon parallax measurements with a 7% margin of error, is roughly 610 ly. It is visible to the naked eye with an apparent visual magnitude of about 5. This is a red giant star with a spectral classification of M3 III. The interferometry-measured angular diameter of this star is 6.70 ± 0.15 mas, which, at its estimated distance, equates to a physical radius of about 137 times the radius of the Sun. It is classified as a semi-regular variable star and its brightness varies by an amplitude of 0.0636 in magnitude. The identified pulsation periods are 32.3, 38.5, and 44.9 days.