Thulium iodate is an inorganic compound with the chemical formula Tm(IO3)3.

It can be prepared by the hydrothermal reaction of periodic acid and thulium periodate in water at 160 °C.

[1] Its crystals can also be crystallized in boiling nitric acid.

[2] Its solubility in water at 25 °C is 1.467±0.001 10−3 mol·dm−3).

Adding dimethyl sulfoxide to water will reduce the solubility.