Between September 2016 and August 2017, we conducted year-long reciprocal transplantation experiments using the cold-water coral Desmophyllum dianthus along natural oceanographic horizontal and vertical gradients (vertically: 20 m to 300 m depth and horizontally: head to mouth of fjord) in Comau Fjord to study seasonal changes and the acclimatisation potential of its biochemical composition. Seasonal energy reserves (proteins, carbohydrates and lipids) and the C:N ratio of native and novel (cross-transplanted) corals were measured at six shallow (A-F, 20 m) and one deep station (Ed, 300 m) during autral summer (January), autumn (May) and winter (August). The calcification rate of the corals was also measured seasonally and the data are available here: doi:10.1594/PANGAEA.945072.