During its third quarter earnings call in August, Apple confirmed that Apple Pay would be expanding to Finland, Denmark, Sweden, and United Arab Emirates before the end of 2017. So far, the mobile payments service hasn't yet appeared in any of these areas, and a rumor about Germany gaining Apple Pay functionality by September has also failed to materialize.
Currently, Apple Pay is available in the United States, United Kingdom, China, Australia, Canada, Switzerland, France, Hong Kong, Russia, Singapore, Japan, New Zealand, Spain, Italy, Taiwan, and Ireland. In a future update to iOS 11, Apple Pay will also gain a new person-to-person payments feature -- Apple Pay Cash -- so that users can transfer money to one another within Messages. This feature will only be available in the U.S. at launch.
Update 1: MacPro has reported that Finland and Denmark could see the debut of Apple Pay next week as well.
Update 2: MacPro has now shared the retail partners Apple Pay will have in Sweden at launch: Pressbyrån, 7-11 and Elgiganten.