Internal alkyne hydration using gold(I) catalysts often shows < 5:1 regioselectivity. To explore factors that control selectivity, [(IPr)Au] + paired with the weakly coordinating anion [IMP-H] was employed in additive free hydration reactions. Solvent influences the anti-Markovnikov selectivity of alkylarylacetylene hydration. Although temperature does not impact selectivity, [(IPr)Au(NCMe)][IMP-H] (C1) is an effective precatalyst for alkyl/alkyl and alkyl/aryl acetylenes at ambient temperature. Overall kinetic behavior of C1 resembles that of other Au hydrofunctionalization reactions of [(IPr)Au] + , where nucleophilic attack and/or proton transfer are turnover limiting. Prospects for improving regioselectivity are discussed.