Hello there SG, thank you for taking the opportunity to ask us your question about the Samsung Galaxy A57 5G. The advertised unlocked Galaxy A57 5G is the U.S. version of this device and is compatible with AT&T, Boost Mobile, Cricket, Google Fi, H2O Wireless, Metro by T-Mobile, Sprint, US Cellular, and T-Mobile. Please reach out to the compatible carrier of your choosing to inquire if this device would be functional while in Sri Lanka. If you have additional questions afterward, please feel free to reach out to Support. Thank you for being a loyal Samsung customer. - Debra