dansachs

From https://www.medicare.gov/coverage/travel-outside-the-u.s.

Medicare usually doesn’t cover health care while you’re traveling outside the U.S. There are some exceptions, including some cases where Medicare Part B may pay for services that you get on board a ship within the territorial waters adjoining the land areas of the U.S. However, Medicare won't pay for health care services you get when a ship is more than 6 hours away from a U.S. port.

When we went to Paris, pre-pandemic, we were glad we got tickets to both the Louvre and the Eiffel Tower before we left the States. We avoided some big-time lines by planning in advance.