SEA Checkpoint 4 security wait times: what to expect
From October 12 to November 9 we logged 60,503 security checkpoint readings at SEA Checkpoint 4. The standard lane averaged 8 minutes. 79% of standard-lane readings were 10 minutes or less, and none were over half an hour.
That is 1 minute longer than the SEA average of 6 minutes.
When the line is longest
The standard line at Checkpoint 4 is longest around 9 AM, when it has averaged 13 minutes, and shortest around 2 AM, at 3 minutes. By day of the week, Friday has been the heaviest (10 minutes on average) and Saturday the lightest (6 minutes).
| Time of day | Standard |
|---|---|
| Early morning (4–8 AM) | 9 min |
| Morning (8 AM–noon) | 11 min |
| Midday (noon–4 PM) | 8 min |
| Evening (4–8 PM) | 6 min |
| Night (8 PM–4 AM) | 6 min |
Average wait across the last 28 days. A dash means the lane is usually closed then.
PreCheck at Checkpoint 4
The feed for Checkpoint 4 does not report a separate TSA PreCheck line, so the figures above cover the standard lane only.
How early to arrive
To plan your arrival, use the worst hour rather than the average: at Checkpoint 4 that is 13 minutes in the standard lane around 9 AM. Allow that on top of your airline's check-in and bag-drop deadlines, and more on Fridays and holiday weekends. The live board above shows what the line is doing right now, and the chart projects the next 12 hours.
Other terminals at SEA
| Terminal | Standard avg | PreCheck avg | Busiest hour |
|---|---|---|---|
| Checkpoint 1 | 5 min | — | 1 PM |
| Checkpoint 2 | 6 min | — | 2 PM |
| Checkpoint 3 | 8 min | — | 10 PM |
| Checkpoint 5 | 3 min | — | 7 AM |
| Checkpoint 6 | 9 min | — | 7 AM |
Where these numbers come from
Each airport publishes its own checkpoint wait estimates. This site reads them every minute and keeps every reading. Closed lanes are left out of the averages, and times are local to the airport. The averages above cover the last 28 days and are recalculated every hour. The posted wait is the airport's estimate, not a timed measurement, so treat it as a guide.
The full archive is free to download as an open dataset, and the about page explains who runs the site and why.