"It's something they'll remember for a long time, I think."
The students visited a host of South African landmarks, including Table Mountain, the Swartberg Mountain Range, the Cango Caves and Sterkfontein - otherwise known as the Cradle of Humankind - where fossils of some of the first humanoids had been discovered.
"We targeted some key features of the landscape," said Mr Bouton.
"The Swartberg pass is particularly famous - geologists from all over world visit it every year. Table Mountain is the oldest mountain in the world.
"The Cango Caves are one of the Wonders of the World. They're quite spectacular."
While visiting the caves, the students got to sample the famous acoustics - one of the St Matthew's students sang and the boys performed the Rathkeale College haka.
Another highlight was Kruger National Park, where students got to pat fully-grown lions and ride elephants bareback.
"We went on walking safaris and we saw the rhinos less than 100m away," said Year 12 student Matthew Murdoch.
A key part of the Geotour was visiting the Missionvale Care Centre which provides food, clothing and education to children in need, for which Rathkeale has been fundraising throughout the year.
Student Aimee France said she felt humbled by the spirit of those she met at the centre.
"It makes you feel so lucky for what you have," she said. "It struck me how happy the people we met were, and they have nothing. They were still smiling and waving for our cameras."
Matthew Murdoch said one of the important things he learned was the importance of protecting our surroundings, especially after visiting the Cango Caves.
"People keep snapping off the stalactites in the caves. They're thousands of years old, and they only grow 7mm every 100 years. People think they're souvenirs."