Radioactive iodine isotopes play a pivotal role in radiopharmaceuticals. Large‐scale production of multi‐patient dose of radioiodinated nuclear medicines requires high concentration of radioiodine. We demonstrate that tetrabutylammonium chloride and methyltrioctylamonium chloride are effective phase transfer reagents to concentrate iodide‐124, iodide‐125 and iodide‐131 from the corresponding commercial water solutions. The resulting concentrated radioiodide, in the presence of either phase transfer reagent, does not hamper the chemical reactivity of aqueous radioiodide in the copper (II)‐mediated one‐pot three‐component click chemistry to produce radioiodinated iodotriazoles.