The rare notable event of this resort is, in 1946, when President Hồ Chí Minh invited the Former Emperor Bảo Đại to Hanoi as the Senior Advisor, the King resided in Sầm Sơn a few months before coming to Hong Kong.

The press of the opposing forces with Việt Minh then satirized that "Vietnam's royal capital moved to Sầm Sơn".

In the following years, Sầm Sơn was constantly planned and upgraded to become a free resort for the working class under the help of experts from the Soviet Union, Bulgaria and China.

According to contemporary regulations, in addition to government officials, only those who achieve high results in learning and labor are allowed to take vacation on this beach.

However, due to the harsh climate of Thanh Hóa province, Sầm Sơn was almost only opened to visitors from the middle of spring (February or April) to the end of autumn (October).

The Thanh Hóa provincial government invested US$375,000 to upgrade infrastructure along the sea, on water supply, lighting systems and an information network to prepare for the festival.