When he was 16, Harel began preparations to emigrate to the British Mandate for Palestine. During this preparatory year he worked in agriculture with the aspiration to join a kibbutz. With the outbreak of the 1929 Hebron massacre, his friends decided to move up their emigration date in order to reinforce the Jewish settlement in Palestine. Documents were prepared for the 17-year-old Harel stating that he was 18 and eligible for a British visa. At the beginning of 1930 he immigrated to Palestine. He crossed Europe from north to south to board a ship in Genoa, carrying a pistol that he concealed in a loaf of bread.