Beatrice Seddon was educated at Rangi Ruru Girls’ School, attended a finishing school in England, and then returned to Christchurch to attend art school under the tutelage of Sydney Lough Thompson and Margaret Stoddart. During World War I, Beatrice Seddon served as a volunteer ambulance driver at Codford on Salisbury Plain, and this role included caring for recuperating officers. After contracting measles at Codford, Seddon went on holiday to St Ives, Cornwall where she met and befriended artist Frances Hodgkins, and while in St Ives, Hodgkins painted a portrait of Seddon (commissioned by her), titled Portrait of Miss Beatrice Wood, 1918.
Seddon painted and exhibited throughout her lifetime, with many of her works inspired by her garden. She had lessons with Frances Hodgkins in London from ca 1914–1919.