A nonblocking 3×3 polymer thermo-optic (TO) switch array based on the total-internal-reflection (TIR) effect is demonstrated. The switch array consists of three 2×2 TIR TO switch elements with a total device length of 15.5 mm, and achieves nine switching states with no more than one switch element working. The fabricated 3×3 TO switch array shows excellent switching performance with low crosstalk for all switching states of less than -20 dB. The power consumption of each switch element is below 53 mW, and the switching rise time and fall time are ∼450 and 550 μs at 1550 nm wavelength, respectively.