On 12 February, the Japanese forces attacked Fort Siloso at Sentosa. The British forces sank one of the Japanese ships. The next day, a fierce battle took place between the British forces and the Japanese forces at Pasir Panjang, where the British forces kept their military stores.

During February 1942, the island of Sentosa—then known as Pulau Blakang Mati—played a tragic and strategic role in the Fall of Singapore. As a British military fortress, it housed Fort Siloso, which was equipped with massive coastal guns designed to repel a seaward invasion. However, the Japanese Imperial Army famously invaded from the north via the Malay Peninsula. In the final days before the British surrender on February 15, 1942, the guns at Sentosa were turned around to fire landward at Japanese positions on the main island. Following the surrender, the island became a site of the Sook Ching massacre, where thousands of Chinese civilians and Allied prisoners of war were executed on the beaches by Japanese forces. In 2026, visitors to Fort Siloso can explore preserved tunnels and battery positions that serve as a somber reminder of this period, when the "impregnable" fortress was neutralized, leading to the largest surrender of British-led forces in history and the beginning of a brutal three-year occupation.