The start of his official retirement falls on his 79th birthday today. He will be celebrating with friends and family at a private gathering.
He announced in July that he would be "slowing down" because his schedule had become too punishing.
"Instead of growing old gracefully, at home with my family reading and writing and praying and thinking too much of my time has been spent at airports and in hotels," he said at the time of the announcement.
Tutu was ordained as an Anglican priest in 1960 at the age of 30 and quickly became one of the most outspoken critics of apartheid.
He was awarded the Nobel Peace Prize in 1984, and in 1986 made history when he became the first black South African to be made Anglican Archbishop of Cape Town.
It was at this time that Tutus international stature grew and he came to be a figure synonymous with justice.
He was later appointed chair of the Truth and Reconciliation commission, a body set up to investigate crimes committed in the apartheid era, and is credited with coining the term Rainbow Nation to describe the diversity of the South African people.
Although he retired as Archbishop of Cape Town 14 years ago, he continued to command the worlds attention, challenging injustice and working for peace and reconciliation in areas of conflict.
He has indicated that he will continue his peace and reconciliation work as part of The Elders, a group of distinguished leaders set up to help mediate in conflict situations. Christian Post