A new resin selective for Sr has been developed and characterised for the direct binding of 90Sr from environmental waters with minimal pre-treatment. The new selective resin comprises of a mixture of two extractants, 4,40(50)-bis-t-butylcyclohexano-18-crown-6 and di(2-ethyl-hexyl)phosphoricacid, sorbed onto Amberchrom CG-71. Sr uptake is shown to be high (the distribution weight coefficient Dw 4100 mL/g) across a range of environmentally realistic conditions (pH 2–8 and up to 11,500 mg/L NaCl, 500 mg/L Ca, 400 mg/L K and 1300 mg/L Mg). The Sr capacity of the resin is shown to be 7.7 +/- 0.4 mg/g, meaning that the resin has a sufficient capacity to quantitatively remove Sr from most environmental water samples. The reasonably fast uptake kinetics of the resin (95 +/- 4% of strontium bound within 30 min) results in a resin that is applicable to both batch- and column-type separation procedures. A range of potentially co-extracted radio-elements have been identified and an elution scheme has been developed to separate interferences, including 90Y, from 90Sr. The clean elution of 90Sr permits immediate measurement by radiometric means, with no need for complicated spectral processing or waiting for secular equilibrium between 90Sr and 90Y. The characterised resin is applicable for use in rapid determination procedures, enabling the swift analysis of water samples required by monitoring schemes at contaminated nuclear sites and in the aftermath of nuclear accidents.