Laura Campbell-Preston was attacked while swimming with friends in a waterhole on 2 May. No one else was hurt.
She had been spending a year before going to university teaching English in a school in the village of Moshi which was arranged by the London-based charity World Challenge.
Her family live in Taynuilt, Argyll. Her parents Robert, 46, and Rosie, 45, run Inverawe Smoke House, which sells smoked salmon by mail order.
Her sister Clare, 23, said last night: "Five of them went swimming in a waterhole. It was known to be safe but there had been heavy rain and a random crocodile got in. She was attacked and killed."
She added. "It was no one's fault and Laura was not being reckless. It was a safe waterhole and one that was always visited."