I am flying JFK-SFO on AA and SFO-MRY on UA. Does the SFO/bay area county mandatory quarantine requirement complicate my situation? Do I need to leave airside to re-check in for the second leg after arriving in SFO?

Any person who is solely transiting through San Francisco County and not staying overnight is exempt from the health order mandating a travel quarantine.

Please refer to the following:

Also - some supplementary information:

1. City and County of San Francisco and County of Santa Clara are the only 2 counties in the Bay Area that have mandatory travel quarantine.

2. When many do not consider, County of Monterey is within the Bay Area boundary per the State. So in theory, other than the additional travel quarantine, Monterey's current COVID-19 measures should align with other "traditional" Bay Area counties.

The AA and UA terminals are not connected, so it would require another round of security. Are you on separate tickets with each carrier?

Also, SFO is in San Mateo County, if you were not aware of that.

Actually, it is more complicated than you mentioned. SFO is indeed within the boundary of City and County of San Francisco, not County of San Mateo (Note - San Francisco Zip Code starts with 941 and San Mateo starts with 940. SFO Zip Code is 94128). However, due to various reasons, in some aspects, San Mateo takes "precedence" over San Francisco.

For example:

1. SFMTA does not provide transportation at SFO, but SamTrans. Also - BART SFO's operation is also funded by SamTrans as well.

2. San Mateo County Sales Tax applies in SFO.

Monterey is in its own county right, and is not subject to SFO/bay area county rules? i.e. if I fly into MRY instead of SFO quarantine is not mandatory?

I am on separate tickets yes... I was hoping there would be something akin to a transit desk where I can check in to my second leg without having to go through security again.

The State has classified Monterey as Bay Area Region. So when the State imposes/relax its restriction for the "Bay Area", it applies to Monterey as well.

Each LHJ (Local Health Jurisdiction) can impose a stricter restriction in addition to what the State imposes.

You're going from one secure domestic terminal to a different secure domestic terminal. There are no transit desks like there might be exiting an international terminal after customs. You'd have to exit and check-in with your second carrier if you have bags to check. Watch your cut-off times on checked bags to make sure you're within the time limits.

The airport may have a San Francisco address and zip, but it is physically located in San Mateo County, and I can't find any evidence they have ceded part of the county to San Francisco County. The county map on the San Mateo County government website defines the area as unincorporated San Mateo County. Also, major crimes at the airport are investigated by detectives from the San Mateo County Sheriff's office, and the San Mateo DA's office in South San Francisco prosecutes crime at the airport. Why would San Mateo County do all this if the physical airport location is in San Francisco County?
https://isd.smcgov.org/county-gis

Here's a Facebook video with a San Mateo County detective explaining the unique relationship between San Mateo County and the airport:
San Mateo detective video

To quote the detective, "San Francisco International is very unique. It's actually the city and county of San Francisco own and operate the San Francisco International Airport. However, it is based in San Mateo County, so because it's based in San Mateo County we have a unique relationship with the San Francisco Police Department who are contracted to patrol here at San Francisco International Airport." Further, "every single criminal case goes to the San Mateo County District Attorney's Office."

I stand by my statement that the airport is in San Mateo County.

Who knows? Maybe by contract.

That's definitely not true. At the minimum - a handful of criminal cases are actually prosecuted by the U.S. Attorney Office in San Francisco.

I stand by mine as well.

It is according to the San Mateo County official website:

According to flysfo website, Monterey is not included in the mandatory quarantine requirement. I'm just trying to confirm that here. You are saying Monterey airport is a part of the "bay area" - maybe so by some definition - but is that the case for flying into MRY?

https://www.flysfo.com/important-tra...-19/quarantine

If you want to be on the safe side, start your trip on UA from EWR, then you can transfer without changing terminals and the hassle of bags recheck and additional security clearance. A good agent at EWR can check your bags all the way to MRY, even on separate (UA) tickets.

Personally, I would say just go on about your trip without the worry about quarantine, especially since you would be on airport property the entire time at SFO. Having to leave one terminal and reclearing at a different terminal - purely academic.

Thanks. I won't have checked bags, which makes things easier...

Monterey, CA, is not considered to be a part of the San Francisco Bay Area. It is in the Monterey Bay Region which is a part of the Central Coast area.

The southernmost county in the San Francisco Bay area is Santa Clara County.

Please let me reiterate that the San Francisco County quarantine order does not apply to those who are transiting through the area and are not staying overnight.

Enjoy your trip.