- Sibu City is a city located in the state of Sarawak, Malaysia. It is the capital of the Sibu District and the third largest city in Sarawak, after Kuching and Miri. Sibu is situated at the confluence of the Rajang and Igan rivers, and is known as the gateway to the Rajang River, which is the longest river in Malaysia. The city has a population of around 257,800 people and is an important commercial and industrial center in Sarawak. Sibu is also known for its diverse ethnic communities, including the Iban, Chinese, and Melanau people. The city has a mix of modern developments and traditional longhouses, making it a unique destination for tourists.