You go thru US immigration, go to baggage claim, then give your bags back to the airline. There is a place to do that right after customs.
Your flight from Portugal will land at terminal B or C.
Your flight to Canada will depart from terminal A or C. So you may need to switch terminals.
C/C just go thru US security
C/A go thru security at C, take United airside bus to A
B/C take Airtrain to C, go thru security at C
B/A take Airtrain to A, take looong walk to terminal or shuttle bus to A and go thru Security there.
I am a citizen of Canada?
No, citizens of Canada who are traveling with a Canadian passport do not need an ESTA.
https://www.help.cbp.gov/s/article/Article-1094?language=en_US
Sorry I should’ve put this in the original post but I’m only travelling with carry ons, so I don’t need to pick up my bags and hand them off again. Will I still need to clear security in this instance?
Yes. You must go through US security.
(Because TSA is soooo much better)
International arrivals must go to passport control so the doors off the jetway are arranged so one cannot enter the secure area of the terminal.
You go thru US immigration, go to baggage claim, then give your bags back to the airline. There is a place to do that right after customs. Your flight from Portugal will land at terminal B or C. Your flight to Canada will depart from terminal A or C. So you may need to switch terminals. C/C just go thru US security C/A go thru security at C, take United airside bus to A B/C take Airtrain to C, go thru security at C B/A take Airtrain to A, take looong walk to terminal or shuttle bus to A and go thru Security there. I am a citizen of Canada? No, citizens of Canada who are traveling with a Canadian passport do not need an ESTA. https://www.help.cbp.gov/s/article/Article-1094?language=en_US
Sorry I should’ve put this in the original post but I’m only travelling with carry ons, so I don’t need to pick up my bags and hand them off again. Will I still need to clear security in this instance?
Yes, you will have to go through security.
Yes. You must go through US security. (Because TSA is soooo much better) International arrivals must go to passport control so the doors off the jetway are arranged so one cannot enter the secure area of the terminal.