If Possible, you ought to allow 3-5h of transit time in Johannesburg, so you have ample time and energy to capture your connecting flight. Transiting in Johannesburg is rather simple; merely Keep to the indications for ‘International Transit’. The flight from Johannesburg to Harare can take about 1h 30m. Nationwide https://www.theluxurybooking.co.uk/flights-to-zimbabwe-from-london/