Three rovibrational bands of Ar-D2O and two rovibrational bands of Ar-HDO were observed in the 1.5 μm range by continuous wave cavity ringdown spectroscopy. Their analyses led to the determination of rotational constants for the upper states and vibrational shifts indicating that the potential energy surface is only slightly affected by the vibrational excitation. Some Coriolis couplings were identified. The observed lines were fitted to retrieve a 3.5 ns lifetime of the upper state, showing that even with a triple or double excitation quanta in the water subunit, the Ar-D2O and Ar-HDO complexes are long-lived species.