TTC’s 18 brands include Trafalgar, Uniworld Boutique River Cruises, Contiki and Insight Vacations.
TTC chair Brett Tollman said: "For more than 104 years, our family has built TTC into an industry leader known for exceptional service and innovation.
"Without a next generation to lead TTC, the time has come in our strategic succession plan to select a new owner with a proven track record and who shares in our vision and customer-first values.
“We will support a seamless transition and are confident the team at Apollo will continue driving the business forward to meet growing global demand for touring, river cruising and specialist and adventure travel.”
Apollo private equity partner Michele Raba added: "TTC has a leading collection of brands that we believe we can take to the next level as an Apollo Funds portfolio company, leveraging our extensive experience in the travel, tech and hospitality sectors.
“We’d like to thank the Tollman family for trusting in our good stewardship of the business they’ve built for more than a century and look forward to an exciting next chapter in which TTC can serve as a platform for growth."
The transaction is subject to due diligence and is expected to be concluded by the end of this year.
Apollo has previously invested in Norwegian Cruise Lines, Sun Country Airlines and Diamond Resorts.
Its most recent travel interest was in 2022 when it acquired the 7,000-room Venetian Resort in Las Vegas, pledging to invest $1 billion upgrading it.
TTC was founded in 1920 in South Africa and has been family run for the past 104 years.
In 2022, Contiki, Costsaver, Trafalgar, Insight Vacations and Luxury Gold were brought together in the UK under the TTC Tour Brands banner, aiming to enhance agent service.
Later that year, TTC combined its UK, Ireland, Europe and South African offices to create a new EMEA region.
