Hi there @Kenlyons and welcome to the Bose Community!
I hope you have fun on your trip! I can confirm that the Sleepbuds can be used in different countries as long as you are using the correct plug adapter! The plug that comes with the system is auto-sensing at 100-240v, 50/60Hz, meaning that if a safe adapter is used this will be fine.
I hope this helps you prepare smoothly for your trip, and please let me know if you have any other questions 😊!