Keable went up to Magdalene College, Cambridge, in 1905. His peers there included the future Everest explorer George Mallory and Arthur Tedder, 1st Baron Tedder. Though his contemporaries described him as a quiet, devout student who initially associated only with other religious-minded men, he later became more sociable and rowed in the college second eight. He took a first in the History Tripos, graduating with his BA in 1908 and receiving his MA in 1914. At Magdalene he was a great friend of Arthur Grimble, the future commissioner of the Gilbert and Ellice Islands (Kiribati). Grimble's daughter, in a biography of her father, described the undergraduate Keable as devout, earnest, somewhat introspective and deeply literary. She records that he spent his university vacations on missionary work. He is known also to have taught in East Africa under YMCA auspices, and to have climbed Mount Kilimanjaro.