A legendary tale explains that in the early days, an elephant, a pig and a frog challenged one another to reach the Johor shores from mainland Singapore. The stakes were high, as those who did not succeed would be turned into rock. The frog, being the first to try, failed to cross the straits and was turned into Pulau Sekudu. Pulau Sekudu literally means Frog Island in Malay.
The elephant and the pig were the next to attempt the feat. They did not make it too, thus both of them fused together to become the main island of Pulau Ubin.