Nowadays, liquefied natural gas (LNG) carriers are the main merchant fleets for the transport of natural gas for energy. The large LNG carrier has a more efficient freight cost (approximately 7.8 USD/MMBTU) than a small-scale LNG carrier (SSLNGC; approx. 12,8 USD/MMBTU). Another method must be introduced to make SSLNGCs more cost-efficient. As such, this work conducted an experiment to improve the design of SSLNGCs via design and cost optimization by combining a value engineering approach and multi-objective optimization to decrease hull resistance and lower construction material costs by adjusting the ship dimension ratio. By improving the conceptual design and using semi-integrated numerical simulations, the final result showed improvements in SSLNGCs by decreasing the hull shell area by 1.57% to reduce the construction material needed and total ship resistance by 8.3%.