However, the calm tides still possess hidden dangers, so following safety instruction is strongly advised:

• Carefully follow the instructions and conditions before swimming or surfing.

• Always swim in a group of at least 3-5 people. Remember to warm up properly.

• Researchers say swimming ability is severely decreased in cold water so no matter how confident you are at you swimming, try not to swim too early in the morning or too late in the afternoon. The average temperature of Halong Sea is around 19-25 Celsius degree, in which the area near the shore (shallow area) is recorded approximately equal to the environment temperature.

• Knowing your own swimming ability to choose suitable beach activities.

• Diving as deep as possible to evade huge waves in case you don’t have enough time to get away from it. Luckily, this seldom happens in Halong.

• While surfing, do not ride waves in a straight line toward the shore. Instead, surf at a small angle to the waves. Stay away from the white water in the center of the wave to avoid "over the falls".

• Never swim in deep water or when you don’t know exactly how deep it is.

• Never swim while intoxicated. Precedents of death due to hypothermia and other accidents have been recorded in Halong.

• Try not to sunbath for too long, you might catch sunburn.

• Halong Bay water is pretty warm during winter so feel free to swim or dive from your junk, however, try to cover yourselves immediately when you are done with the swimming because you might catch a cold. The temperature during winter can get as low as 10-15 Celsius degree.