The 10-night journey begins with a two-night hotel stay to explore the mystical 12th-century temples of Angkor, the world's largest complex of its kind, before discovering the hidden charms of Cambodian capital Phnom Penh.
Launched by France-based international cruise company CroisiEurope, the tour that ends in Ho Chi Minh City is scheduled to depart on Nov. 26 and costs 2,406 pounds ($2,712), including excursions.
The Mekong is a trans-boundary river in East Asia and Southeast Asia. It is the world's 12th longest river and the third longest in Asia, flowing through many countries including Cambodia and Vietnam.
The Times list also included a cruise tour to Central America, sea voyages to the Indian Ocean, French Polynesia and South America.
Vietnam reopened its borders to foreign tourists in mid-March this year.
So far this year, the country has received 1.87 million foreign visitors or 30% of its annual target.