When to check-in for a domestic flight that is connecting to an international flight?

You treat the domestic leg like any other domestic flight for which you would be checking luggage.

I would agree totally With JHK. Check in as you would for a domestic flight. No extra time needed. One small point I would add is that you should have your passport ready as you check in at the originating airport. Whenever I have flown out of my local airport here on the East Coast (Albany International) on an international flight, on a through ticket, transiting through another US airport, I have been asked for my passport at the check in counter. Again, tho, no extra time needed.

If possible check in at the desk/counter using your passport as identification for your first flight. Yes you will probably need to show it again during boarding for the international leg but your information will already be in the system. No need to arrive for your first leg two or three hours for your first leg. Arrive as you would normally do so for that domestic flight.

SEA with cruise season is a mess, so I would not risk the 2 hours and would go with 3. SEA is absolutely mobbed with cruise traffic in July. So inside the airport, but also traffic at the airport, or trying to approach it, can be a nightmare. Even with Global/Clear, this is what I do here, FWIW.

SEA with cruise season is a mess, so I would not risk the 2 hours and
would go with 3. SEA is absolutely mobbed with cruise traffic in July.
So inside the airport, but also traffic at the airport, or trying to
approach it, can be a nightmare.

Mikliz, thanks for offering your local insights re: flying out of SEA. Now you have me wondering about our domestic flight out of SEA on Mon, Aug 12, and if we should also aim for arriving at SEA 3 hours before flight departure. Our flight leaves at 12:30 PM, so should we aim for check-in at SEA by 9:30 AM? I imagine mid-Aug is not much different than July. We already knew we'd need to build in additional time to return our rental car at SEA, but now I'm wondering if we need to allow yet more time, i.e., return car rental by 9 AM, shuttle to SEA to check in by 9:30 AM? Thanks, and apologies to Melanie for this slight digression.

You "check-in" on line as soon as the airline allows you to. Usually 24 hours prior.

You arrive at the airport at least 90 minutes prior, earlier if it makes you feel better (I shoot for 2 hours early).

Travel is very busy this year. If you do not have something like pre-check or global entry to get you into the short lines of security, I would not arrive in airport less than two hours in advance. If you’re checking luggage, keep in mind you will have to stand in line inside you cannot give it to a skycap

Been in several airports thr last few weeks traveling for business and all of them were busy and that includes small airports. Over the last month I’ve seen several panicked passengers in bag check and security lines.

Yes SeaTac has been a mess lately because of construction, so it is important to be prepared. You can check in online for your Alaska flight 24 hours in advance, so from 12:30 on Aug. 11. Get your boarding pass then— either on your phone or print it out. You cannot get an Alaska boarding pass from kiosks at the airport.

Read the requirements here:

https://www.alaskaair.com/content/airports/washington/seattle/seattle-tacoma-international

If you are checking bags they recommend arriving 3 hours ahead at SaeTac. If not checking bags, you can arrive 2 hours ahead and go straight to security with your mobile boarding pass or printed one.

Since you are checking bags the 3-hour time applies. You must print your bag tags at a kiosk before you get in the bag drop line. Note that this area can be very crowded and chaotic due to cruise ship passengers with lots of luggage, so be sure to read the signs and follow directions to the right spot.

Security lines have been long lately, so I advise you to make a reservation for a spot in line using Spot Saver.

https://www.portseattle.org/SEAspotsaver

You can make it 5 days in advance of your flight, and the site advises you to do it then as the spots do sell out.

Security lines 4 and 5 are closest to the gates used by Alaska (Concourses C and D, and N terminal).

Do you by chance have TSA Pre-check or Clear? If so then you will not need SpotSaver. Just plan on getting to SeaTac three hours prior to your flight. It should make it less stressful.

Thank you Lola for all those details. I think you will be doing a lot of copy/pasting with that information;)

If you have Global/Pre/Clear, you might use checkpoint 1 even though it is further from the Alaska gates. I always try to head to that one as there are no regular lines here, so it moves faster. There have still been times that it gets backed up, but nothing like the other checkpoints.

If your flight is in the C concourse, the gates are really crammed together with limited seating, so often times there is nowhere to sit, so be warned. You might stay in the lounge or the food court area near there until closer to the time to board.

I very rarely check a bag, and even with carryon and Global/Clear I arrive at SEA 3 hours before flights during the cruise season as well as over the holidays.

I appreciate all the advice. I'll get to the airport 21/2 to 3 hours before my departure. I use Spot Saver which I reserve through my Alaska app. Avoid Checkpoint 5. It is super slow compared to the other ones. In my experience Checkpoint 3 is the fastest.

Thanks to all whose home airport is SEA-TAC for providing so much good info and advice. I’m now resigning myself to an even earlier morning departure from Bellevue to make our flight. Another good reason to avoid an early morning flight whenever possible.

I so appreciate how gracious you are with your time, especially Lola and MikLiz!

I wrote my previous post before our most recent experience. We were booked on an 11:15 an Alaska flight tonRenomto join a family get-together at Lake Tahoe. Our travel date was Friday, June 28. Fridays are supposed to be the worst due to cruise ship traffic, and we needed to check bags because I was carrying hiking poles and a lot of food and spices for our part in the joint cooking. I made sure we would arrive at SeaTac in good tinpme for the checked bags, and more than 2 hours ahead for security. We have TSA Pre through Alaska Airlines and Global Entry, but I always make a backup SpotSaver reservation just in case the TSA Pre line is too long.

On this day the bag check went smoothly-Alaska has the lines well organized— but the TSAPre line at Checkpoint 4 was long. We had to queue to even each the checkpoint for entry into that line. And after waiting in the queue for 10 minutes, we were turned away, because for some reason our boarding passes did not show TSA Pre. We never checked because it has been automatic for so long. I think it was because I changed our reservation several times, always over the phone because it was complicated and could not be changed online. And somehow the TSA Pre designation did bot carry through.

At that point I checked and saw that it was 9:30, just in time for our SpotSaver reservation at Checkpoint 5. That was a lifesaver, as the line for non TSA Pre people were hopelessly long everywhere. It worked really well, although my husband was a bit annoyed that he had to take his shoes off, which we usually never have to do. But it probably saved us 20 minutes of standing in a slow-moving TSA line.

Bottom line—-SeaTac is extremely busy this summer. Be prepared, be early, and consider making a SpotSaver reservation.

Lola--Glad you had that backup plan! I do recommend getting Clear. That has saved me a lot at SEA, and we have Global as well. Back in January when we were all headed to CA for my mom's services, we all went through checkpoint 3. Since I have metal in me now, I wandered over to where they told me to go, losing sight of the rest of the family. We all met up near the lounge entrance, but we could not find my husband. I texted him, and apparently when I booked the tickets, his Global number was one off. I don't know how that happened, but the poor guy had to go to the back of the regular line. Under the trip circumstances, he was a very smart man and never said another word about it, lol. He did make sure it was corrected before we flew home.

SeaTac user here. Agree with 3 hours if checking bags. 2 or 2.5 if not depending on the time of your flight.

SeaTac and the traffic around it is a MESS.

A long time ago I was told that the Pre-Check mark would be dropped from your ticket on a random bases so that you were forced through the regular security line as a double check of the system. Has never happen to me. Could be an old urban tale.