Originally Posted by
off2rome
Quick question. I have a flight to LHR from the US. Then a connection to LIS.
Is the Antigen test 24 hours before boarding referring to boarding your flight to Lisbon from LHR or your original point of departure?? In other words, when does the 24 hour clock start?
For the USA the "clock" is not, and has never been, 24 hours. It's the day of departure or the day before departure, see the CDC website for very clear explanations of this. Personally I would make it the "day of travel or the day before travel" relating to LIS rather than LHR, if there is an overnight stay, and it's easy / cheap to do the test in LIS. But if it's one ticket and the connection is not unduly long in LIS, the rules relate to departure time in LHR rather than LIS.