Summer is a good time to cruise on Halong Bay but the best time of year is during the spring or fall. Because the bay is situated in the northern part of the country, it can get colder in the fall and winter, and though you won't see extremes such as blizzards, it's still a lousy place to be when it gets cold.

Tip: You should bring a swim suit with you, night's swim in the phosphorescent water is also very nice (must be before your drinks)