SEA Int'l to Domestic short connection
 

Hi - looking to see if 70 minutes is enough for an international to domestic connection in Seattle.
Flying in J on ANA, connecting to UA (Y) on separate tickets. Hand baggage only, US Citizens with TSA Precheck (not sure if that matters for arriving pax). Will potentially use Mobile Passport - will depend on what the immigration lines look like.
ANA flight arrives at 11:25 - UA (SEA-DEN) departs at 12:39 - does anyone know if 70 minutes is sufficient at SEA?

Thanks in advance for any info.

SEA provides express cards which can get you to express lanes at immigration and customs. It is a huge card and you are supposed to make it visible to the staff there and they will run over to help you. It is good until you clear customs then you have to go to the main flow of transfer security. SEA is pretty well in order in general (probably because it is not all that busy).
I got the card for a 1H 50M connection on HU-AS where my first HU leg was delayed. There was someone waiting at the arrival gate giving passengers with tight connections the express cards. You probably won't get it automatically since your trips are on separate tickets but hey no harm to ask. Just so you know this option exists.

SEA is quite easy for connections. The bottleneck comes from immigration, so if you can make it through fast enough, you should be fine.

It is possible but very tight.
There are a ton of international flights all arriving around 12pm to Sea and immigration can get very backed up.

one time, the immigration line stretched all the way to the plane door...

if the inbound flight gets delayed, there will be a lot of people in front of you.

If u have the boarding pass for UA, u can potentially skip going out from the secure area and back in.
The mini trains can take you to the UA terminal directly.
otherwise, would have to exit security, get boarding pass and back in again which would take too long.

In any case, i would pad in more than 70 mins connection but that's just me.

Thanks for all the replies. I'm leaning toward chancing it, will check the inbound for a while to see if it makes it in a little earlier or is delayed, etc. then pull the trigger. Great tip about the express cards. I'm hoping to be able to check in online with UA and get mobile boarding pass, then don't have to exit and re-enter again.

Another possible paper BP source is from UA at NRT. It's possible that they could put something in you record to let SEA know that you might need help getting through the CBP and TSA checks. Depending on when you get past Japanese Immigration you should be able to ask at either the UC (preferred) or the Transfer Desks if they're open. The UA people at NRT are good at helping with down line issues even with separate tickets, they've flagged me a couple of times connecting in LAX to RNO connecting with OZ going through ICN. I've got GE rather that Pre-Check and 70 minutes would be tighter that I'd do at SEA but the gates UA usually leaves from aren't too far from the South TSA Checkpoint if that one's open. Using the Mobile Passport app will likely help some since you won't be caught in the kiosk lines and just head to the Immigration inspectors but you'll still need to wait for bags and the line at Customs.

Good luck!

Thanks ttuna3 - that's a good idea. I'll definitely swing by the UC at NRT and try there for them to add some notification on our reservation - can't hurt to ask.

OP does not have a connection as he specifically states that he is traveling on separate tickets. He will not receive an Express card at SEA and, while UA will certainly make an entry in his PNR notes (he may call in or stop at any UA counter or UC he pleases), the reality is that nobody will see it and as it is on separate tickets, the chances of UA being of assistance are not great.

A more prudent approach would be to book the later flight (presuming there is one) and SDC on arrival if the transfer works,