Ports · June 23, 2026
The North Harbor of the Northwest Seaport Alliance runs on a handful of container terminals. Here's what lands where — and what it means for getting your box out clean.
The Port of Seattle is the North Harbor of the Northwest Seaport Alliance (NWSA), the combined operation of the Ports of Seattle and Tacoma. Its container business runs through a small set of terminals clustered on and around Harbor Island and the SODO waterfront. Which one your container lands at is set by your steamship line — but it changes the gate, the appointment system and the way the move is run. Here's the rundown.
Terminal 18 is the largest container terminal in the region. It sits on Harbor Island, minutes from I-5 and SR-99, and handles a major share of Seattle's containerized imports and exports. For drayage, T18 is bread and butter — high volume, busy gates, and an appointment system you have to work against the clock. The upside of its size is frequent service; the catch is congestion, which makes watching the Last Free Day non-negotiable.
Terminal 5 was rebuilt to take the biggest ships on the West Coast. The modernization upgraded its berths, cranes and shore power so it can handle the largest container vessels afloat. When one of those mega-ships discharges at T5, a lot of boxes hit the yard at once — which means appointment availability and chassis supply tighten right when everyone wants their freight. Planning the pull early is what keeps a big-vessel discharge from turning into demurrage.
Terminal 30, just south of the stadiums in SODO, rounds out Seattle's container capacity and takes some of the overflow. It's smaller than T18 and T5 but works the same way for drayage — same harbor, same appointment discipline.
The terminals share a harbor but not a gate or a portal, so a carrier has to track each one's appointment system and free-time clock separately. From our Kent hub, the Seattle terminals are roughly 20 minutes north — close enough that the dray is short and the empty return is quick, whichever terminal your box lands at. We dispatch against every Seattle terminal daily, so the line's choice of T18, T5 or T30 never becomes your problem. (For the full picture, see Port of Seattle drayage and how the harbors compare in Port of Tacoma vs. Seattle.)
The main container terminals are Terminal 18 (T18), Terminal 5 (T5) and Terminal 30 (T30), all part of the Northwest Seaport Alliance's North Harbor.
Terminal 18 is the largest container terminal in the Puget Sound region, located on Harbor Island in Seattle, handling a major share of the area's import and export containers.
Terminal 5 is a modernized Seattle container terminal rebuilt to handle the largest container vessels on the West Coast, with upgraded berths, cranes and shore power.
Usually not — your steamship line and service decide the terminal. What you control is using a carrier that works all of them, so the choice doesn't limit your options or your timing.