Ideally, it is best to permit three-5h of transit time in Johannesburg, so that you've got enough time and energy to catch your connecting flight. Transiting in Johannesburg is rather effortless; just Adhere to the indications for ‘International Transit’. The flight from Johannesburg to Harare normally takes about 1h 30m. https://www.theluxurybooking.co.uk/flights-to-zimbabwe-from-london/