Coconut water has several uses that are beneficial to humans, mainly because of its nutritional and medicinal properties. In this study coconut water samples were collected from the fresh mature coconuts and from packaged processed coconut water to measure the radon concentrations in them. The results were used to estimate the annual effective radiation dose to the general adult population from ingestion of coconut water. The samples were analyzed for radon concentrations using the Durridge RAD-7 radon detector. The results of measured radon concentrations for the fresh mature coconut were ranged from 381.10 Bq•m −3 to 1716.80 Bq•m −3 . The results for packaged processed coconut samples ranged from 68.08 Bq•m −3 to 556.85 Bq•m −3 . The mean values for the samples were (1081.40 and 222.78) Bq•m −3 for the fresh and processed samples, respectively. The estimated mean annual effective doses (AED) due to ingestion of coconut water were 0.41 and 0.08 μSv•y −1 for fresh and processed samples, respectively. These values are significantly lower than the safe limits recommended by the World Health Organization and the European Commission of 0.1 mSv•y −1 and the maximum contamination level (MCL) of 11,000 Bq•m −3 by the United States Environmental Protection Agency and so do not constitute a risk to consumers of coconut water.