Sea-Tac Airport adding 11 new security lanes this year

Passengers will notice new signs at the Seattle-Tacoma International (Sea-Tac) Airport on Thursday. All the security checkpoints have been renumbered.

There are now six security checkpoints at the airport, though only four of them are in operation. The re-numbering is needed as the airport prepares to open a brand new checkpoint at the south end of the main terminal.

“Thursday morning, it’s basically just a signage situation for folks,” Sea-Tac Airport’s Perry Cooper said. “Nothing’s changed from a checkpoint standpoint. You’ve got your favorite one. Still go to that space. It will probably be a new number than what you’re used to.”

The old baggage claim is gone near the international arrivals gate, and the new checkpoint has taken its place. It’s the only security checkpoint on the lower level of the main terminal.

“We’re going to be able to have five checkpoint lanes down here as whereas we only have three on the current checkpoint,” Cooper said. “We’re really excited for it.”

Using the lower level to expand capacity was the only way to do it with such limited space.

“It’s one of those challenges that we have with our small footprint,” Cooper said. “We talked about this for years. We just don’t have space to add another checkpoint on the same level. What we had to do is find a creative way in which we could have another checkpoint increase that capacity.”

So the new Checkpoint 1 is the new checkpoint on the lower level. The numbers go up from south to north, so the checkpoint currently undergoing renovations at the north end will be Checkpoint 6, not 5, going forward.

Looking at the new checkpoints at Sea-Tac Airport

What’s cool about this new checkpoint it takes you underneath the main level and into the middle section of the escalators you use to catch the train.

“You’ll come to a space, after you go through the checkpoint, and you’ll make a decision, with help from our customer service, either to go down to the satellite trains and go to your gates from there, or go up specifically into the Concourse A area and the rest of the terminal,” Cooper shared.

It should take a bunch of passengers out of the main terminal, easing congestion all the way around.

This new southern checkpoint is expected to open in early June. The newly refurbished Checkpoint 6 on the north end should open before Thanksgiving. Cooper said that it will be a game-changer for passengers.

The security checkpoints ⁦@flySEA⁩ have new numbers today. This is the new checkpoint 1 at the south end of the terminal, which will open in early June. Yes, it’s on the lower level. #chokepoints pic.twitter.com/R26mXkwxEM

— Chris Sullivan (@NEWSGUYSULLY) April 17, 2025

“We’ll go from 28 lanes to 39 lanes overall, once we get these all back up,” he explained.

How is the airport doing in getting people through the airport?

94% of passengers made it through security in 30 minutes or less last year. That’s up to 98% in the first three months of 2025.

Adding this extra capacity should make a huge difference.

Chris Sullivan is a traffic reporter for KIRO Newsradio. Read more of his stories here. Follow KIRO Newsradio traffic on X.

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