Singapore has overtaken Hong Kong to become the most expensive city in the Asia-Pacific region for expatriates (2nd most expensive in the world) as at July 2018.

Hong Kong is the now 2nd most expensive city in Asia-Pacific and 3rd most expensive city in the world.

Tokyo is the 3rd most expensive city in Asia-Pacific, and 7th globally. Japanese locations have remained high in the rankings with 5 cities in the Asia-Pacific top 10 most expensive places.
https://www.xpatulator.com/cost-of-living-article/Asia-Pacific-Expat-Cost-of-Living-Comparison_709.cfm