Tui has ordered 11 new aircraft at a cost of $1.4 billion.
The order for 10 737 MAX 8s and one 787-9 Dreamliner as well as an option for one additional 787-9.
With today’s order, Tui Group now has three unfilled orders for 787-9s and 70 for the 737 MAX.
Executive board member with responsibility for Tui Group Airlines David Burling said: "We are committed to investing in our aircraft fleet in order to keep improving our customer’s experience and to grow ahead of the market.
"This includes the expansion of our long haul holiday programme and providing more choice of flight times and durations to new destinations.
“Our customers tell us how much they appreciate the investment we are making in new aircraft, so we’re pleased to make flying with Tui an even more enjoyable experience with this latest order."
He added: "With the 737 MAX, we will be able carry our short-haul customers further, in greater comfort, more efficiently and with an even lower environmental impact.
“The 737 MAX will contribute significantly towards fulfilling our commitment to further reducing the carbon intensity of our operations.”