Explore Worldwide is discounting 20% on more than 1,500 trips to encourage new year business.
The promotion by the adventure travel operator covers bookings made before January 18 for travel until the end of 2024.
Destinations include Iceland, Vietnam, the Baltic states, South Africa, Sri Lanka and Costa Rica.
The company pledged that no additional price changes will be made once travellers have booked their 2024 trip and secured it with a deposit.
Managing director Michael Edwards said: “The Explore Big Blue Sale is back with even more worldwide departures to choose from.
“From exploring the blue city of Chefchaouen in Morocco to snorkelling the crystal blue waters in the Maldives, there are a whole host of once-in-a-lifetime adventures in store for 2024.
“Choose from small group classic discovery, walking or cycling tours, or why not opt for a family adventure for everyone to remember.”