The flux of 222Rn from the ocean surface has been measured by the accumulation method off the windward coast of the island of Hawaii. A figure of 74¿8 atoms m-2 s-1 was obtained, compared with a range of values from 11 to 116 atoms m-2 s-1 calculated from near-surface 222Rn concentration profiles in seawater obtained by other investigators. If these results are representative, the total oceanic contribution to 222Rn in the global atmosphere is only about 2% of all 222Rn exhaled from continents. Fluxes obtained by the accumulation method in shallow bay waters nearshore were intermediate between the very low value measured in the open ocean and the values obtained onshore.