We report bulk superconductivity (SC) in Ca3Ir4Sn13 by means of Sn-119 nuclear magnetic resonance (NMR) experiments. Two classical signatures of BCS superconductivity in spin-lattice relaxation rate (1/T-1), namely the Hebel-Slichter coherence peak just below the Tc, and the exponential decay in the superconducting phase, are evident. The noticeable decrease of Sn-119 Knight shift below T-c indicates spinsinglet superconductivity. The temperature dependence of the spin-lattice relaxation rate (119)(1/T-1) is convincingly described by the multigap isotropic superconducting gap. NMR experiments do not witness any sign of enhanced spin fluctuations. (C) 2015 Elsevier B.V. All rights reserved.