And you can forget calling the CDC Covid hotline. I did that Friday with this exact question. She put me on hold, searched her script, and then kept reading to me how I shouldn't take a cruise! Apparently that was the only reference to a boat. I explained it was a one-hour, open-air ferry.

The rule says it applies to people returning to the US by air. Drive from Mexico, no test; fly, need a test. That would imply it's the airplane that is the risk factor.

Some people report that their water taxi didn't request test results, but that's a risky strategy.