Professional expats often benefit from pre-arranged accommodation, at least for the first couple of months of their arrival, or from housing allowances that come with generous job contracts. But this isn't always the case, and for many more expats, rental costs are a financial burden — especially if they live in metropolitan areas. EuroCost International, a company that helps businesses to manage their mobility, has ranked the world's most popular expat cities according to the rental costs for expats. Read also Essential rights to know before renting property abroad The most expensive rents in Asia and OceaniaAccording to EuroCost, the most expensive cities in the world for expats are found in Asia. Hong Kong and Tokyo, known for their extremely high cost of living come first and second respectively on the list with the top 20 cities in the world where you will pay the highest rent as an expat.It's interesting to note that from the 20 cities ranked, seven are Asian cities — similar to 2015's report. Hong Kong with rent prices ranging between USD 2,214 and USD 4,972 per month and Tokyo with a strong yen are followed by Shanghai, Osaka, Mumbai, Beijing, Seoul, and Jakarta. Read also Real estate investment abroad: Should expats build or buy? In the meantime, Sydney takes the 16th position on the list with rents starting from USD 1,978 to USD 3,645 for different types of apartments.Europe's rent costs remain expensive for expatsThis year, fewer European cities rank in the global top 20 with London holding onto its title as the most expensive city for expats in the region. However, since the Brexit vote, rent prices have dropped down drastically in London with the devaluation of the pound against the euro as a direct consequence. Hence, the British capital city is no longer the most expensive city in the world to rent a flat. Read also Petsitting and homesitting for expats: Here's how it works Geneva, Moscow, and Zurich are following London in Europe's ranking. Other major cities such as Amsterdam, Paris, Copenhagen, Kiev, the Hague, and Dublin are also among the cities with the highest rental charges for expats.The report reveals that in 2016 rent prices have significantly increased in the Irish and Danish capital cities. For example, apartment prices now range between USD 1,385 and USD 2,407 in Dublin and between USD 1,294 and USD 2,376 in Copenhagen. Read also Housing rental: small spaces and cost challenges for expats The highest rents in the USAFive American cities are featured in the global top 20 — New York, San Francisco, Washington, Los Angeles, and Miami. Boston and Chicago are entering the top 10 of the most expensive cities to rent in the American continent as a whole. For example, apartment rents range between USD 2,362 and USD 4,088 in Boston and between USD 1,466 and USD 1,703 in Chicago.On the other hand, Sao Paulo in Brazil has moved up the global ranking to one of the most expensive cities in Latin America. Mexico and Panama City are also in the top ten of the American continent. Read also Bare ownership: How expats can benefit amid global housing challenges Living in Africa is expensiveAlthough Africa is still underrepresented in the global ranking, a few cities are known to be costly for expats. Luanda and Juba can be found in the global top 10. Kinshasa and Maputo are also known as the most expensive cities for expat rents, ranking 4th and 5th in Africa. However, many African countries expats prefer to rent a villa rather than a flat. It's worth mentioning that Lagos has moved out of the African top 5 due to the devaluation of the naira.Falling rent prices in the Middle EastNone of the major Emirati and Saudi major cities is in the global top 20. While Beirut and Doha rank 11th and 13th worldwide, Abu Dhabi, Dubai and Riyadh come 21st, 22nd and 30th respectively due to the decrease in rent prices over the past year.