United MileagePlus (Consolidated) - SAN-SFO-HKG(can i check my bag all the way?)

i have a UA flight from San Diego to SFO, i will get my connection flight in SFO, then fly to HKG(my destination). so it's SAN-SFO-HKG
do i have to go to the baggage claim to get my bag then go through the Custom in SFO, then check my bag again in SFO? or i can check my bag all the way from San Diego to HKG in the UA counter at the san diego airport? thanks.

No. You can check your bags all the way to HKG. At SFO, you just move from domesit f gates to international g gates, not even need to go throug the security again.

On your way back if you still fly HKG/SFO/SAN, you do need to claim your bags at SFO for customs check.

Welcome to FT

When coming from SAN to SFO you usually arrive at the domestic terminal and will have to walk to the International terminal; it is about 5-10 minute walk and if you follow the signs to International terminal careful, you can do that without going through security again.
Your luggage should be checked through to HKG where you will pick up your luggage.

On the way back your luggage will have a SAN tag on it but when you arrive in SFO you clear immigration, then pick up your suitcase/s, go through customs and recheck the luggague; you will go through security again and go to the domestic terminal to board your next flight.

If you have access to the UA lounge there is one in the domestic and another one in the international terminal. Both are OK.