Building anything related to an airport in the US is nearly impossible. If you’re lucky, it will take years and cost an absurd amount of money. After a long, long road, it seems that Seattle/Tacoma (SEA) has now passed one of the big remaining hurdles standing in the way of its next phase of growth. This is hugely important considering how the place is bursting at the seams today, but on the downside… it will probably need even more capacity by the time this is done.
The Federal Aviation Administration (FAA) has now approved a “Final Environmental Assessment” and a “Finding of No Significant Impact/Record of Decision” for SEA’s big master plan that it hopes to have completed by 2032, five years behind the previous schedule. That has been a very long road just to get to this point.
This project sounded a lot more impressive long ago when there were fewer passengers using SEA. But as Alaska and Delta continue to grow, the airport hit a record of 52.6 million passengers in 2024. It will probably be a little higher this year. When the work is done in 2032, it will put the airport in a position to handle… 56 million. That’s not a lot of growth, but it’s a start.
The centerpiece of this plan involves a second terminal built to support 19 new gates. This new terminal plan looks like some kind of Rohrschach test. You wouldn’t design something that looks like this in your wildest fever dream, but welcome to SEA where space is at a premium.
The current terminal is in red above. There are four concourses that radiate out of that terminal and then the two satellite concourses. The S gates are where the international operators are, but other than that, there are really two sides here.
On the left side of the image you see concourses A and B. Those are mostly for Delta and WestJet, but there are some other cats and dogs in there too. On the right, you have concourses C and D along with satellite N. Those are all Alaska and a little American. The red terminal in the middle is where the airlines meet for their weekly rumble.
It’s the green bit on the right that will be a new terminal. If this looks weird, it’s because you need more context. The airport is hemmed in on pretty much all sides, so any growth requires some creativity. Here’s some more detail with all of the projects that are planned..
Up is to the west, if that helps to orient you. But as you can see, a lot is going to change. Just to be able to build Terminal 2, SEA has to clear the area out. Airport maintenance, the fire station, and airline support services have to move out with maintenance heading to the top of the picture, the fire station going to the left between the ends of the runways, and airline support going a little to the right. Southbound lanes that head into the terminal also have to go away into a different configuration.
Then there are other expansions and changes as you can see in the map above. If you want more detail, this doc has a little. Or you can go to the master plan website if you find yourself having trouble sleeping at night.
Once all this work is done, I imagine Alaska and Delta will have competed their way right past that 56 million capacity number. It seems like SEA should think about starting now on the next phase which is already part of the plan. They will just create a mirror image of the new terminal to the north (right) to double the gates.
But wait, that’s looking too far ahead. Next up is a State Environmental Policy Act review with public comment sometime in 2026. Even once that is fully approved, well, the FAA says that are 17 issues that have to be dealt with during design and construction, “including potential impacts on air quality, biological resources, land use, historic resources, and hazardous materials.”
Even now the timeline seems to have started to slip with projects now expected to be either done or underway by 2032, meaning not everything will be finished then. I think the terminal is likely to be open by then, barring any further hurdles taking longer than expected.
