The growth of coral reefs has been a controversial subject ever since Darwin's1 subsidence theory. Scientists have argued over the major factors affecting growth2–4, but most have agreed that reefs grow dominantly along their windward margins5–7, a characteristic displayed in the Permian8 and Devonian9 reefs of New Mexico and Western Australia. Recently, however, Adey10 has indicated that the growth characteristics of windward margins are energy related, such that different growth characteristics are to be expected under different energy regimes. The Great Barrier Reef is a high-energy epicontinental shelf reef system on which it has been suggested11–13 that, in the prevailing conditions, windward growth has been subordinate to vertical and leeward growth. We present here results from drilling and monitoring studies demonstrating that reef growth in a transgressive epicontinental shelf environment is first vertical and then backwards, especially on the leeward margin, when the reef reaches the stillstand sea level position.