About 10 miles. Fifteen to twenty minutes clear, and up to forty-five at peak.
Ten miles is barely a journey — except that Lake Washington sits between the two cities, and every crossing is a bridge with no alternative.
The numbers
| Feature | |
|---|---|
| Distance | ~10 miles downtown to downtown |
| Drive time, free-flow | 15–20 min |
| Weekday peak | 35–45 min |
| Main route | I-90 or SR 520 across Lake Washington |
| Transit | Link light rail |
Ten miles taking forty-five minutes is what a bridge chokepoint does to a short trip.
The two bridges
This is the whole geography of the corridor. Both crossings are floating bridges, both are tolled or partly tolled, and there is nothing else.
I-90 runs south of downtown Seattle across Mercer Island into Bellevue. It carries heavy traffic and connects to I-405 on the Eastside.
SR 520 runs north, from the Montlake area across to Medina and Bellevue. It is tolled, and the toll varies by time of day.
Which one: it depends on where in each city you start and finish. From downtown Seattle to downtown Bellevue, I-90 is usually the shorter path. From the University District or north Seattle, SR 520 is the obvious choice.
What matters more than the choice: both bridges are single points of failure. An incident on either one has no diversion — you cannot route around a lake. When one closes, the other absorbs the load and both become slow.
Light rail — the corridor's real change
Sound Transit's Link light rail now crosses Lake Washington, which is a genuinely significant development for this corridor. It is the first fixed rail link between Seattle and the Eastside, and it removes the bridge risk entirely for anyone whose trip fits it.
The 2 Line opened the Seattle–Bellevue crossing on 28 March 2026. Sound Transit's 2026 service plan puts downtown Seattle (International District) to Downtown Bellevue at about 22 minutes in-vehicle. Bellevue Downtown to Westlake is about 25–28 minutes. Those times stay put at peak because the line uses dedicated rail across the I-90 express lanes.
Check Sound Transit's journey planner for the timetable that matches your stations — frequency and first/last trains still change by hour.
Where it wins: downtown Seattle to downtown Bellevue at peak. A fixed twenty-two minutes against a variable fifteen-to-forty-five is the same trip and a completely different planning problem.
Where it does not: either end away from a station, or trips into the wider Eastside — Redmond, Kirkland, Issaquah — where the last mile takes over.
When to drive
| Departure | Typical duration | Notes |
|---|---|---|
| Before 6:00 a.m. | 15–20 min | Free-flow |
| 6:00 – 9:30 a.m. | 30–45 min | Westbound peak into Seattle |
| 10:00 a.m. – 3:00 p.m. | 18–25 min | Best window |
| 3:00 – 7:00 p.m. | 35–45 min | Eastbound peak toward Bellevue |
| After 7:30 p.m. | 15–20 min | Clear |
Direction matters and it is not obvious. Bellevue is a major employment centre in its own right — Microsoft, Amazon offices and a substantial downtown — so this corridor is not a simple suburb-to-city commute. Traffic loads meaningfully in both directions at peak, which is unusual and which makes reverse commuting less of an advantage here than in most metros.
Puget Sound has some of the worst congestion per capita in the country, and the bridges concentrate it.
Tolls
SR 520 is tolled, with rates varying by time of day and by whether you have a Good To Go pass. I-90 has express lanes with their own rules.
For a routine trip the toll is a modest cost. For a daily commute it adds up to a real number over a year, and it is worth pricing against light rail fares if you make the trip five days a week.
Where to stop
Ten miles does not need a stop, but Mercer Island sits in the middle of the I-90 crossing and has services if you need them. It is also the only land between the two shores on that route, which is a useful thing to know if something goes wrong mid-bridge.
Weather
Rain is constant and rarely dramatic, but the bridges at capacity degrade disproportionately when the surface is wet.
Wind is the specific hazard here. Both crossings are floating bridges, and high-wind events can produce lane restrictions or, rarely, closures. When SR 520 closes for wind, I-90 takes the entire load.
Winter ice is infrequent and disruptive out of proportion to the amount — the region has limited equipment and drivers have limited practice. Bridge decks freeze first.
Fog on the lake is common in autumn mornings.
The airport connection
A lot of Seattle–Bellevue trips are really airport trips. Sea-Tac sits south of both cities, and getting there from Bellevue is a different journey with its own considerations — I-405 rather than the bridges. Sea-Tac sits south of both cities; Bellevue uses I-405 rather than the Lake Washington bridges.
The reverse trip
Bellevue to Seattle is the morning problem; Seattle to Bellevue is the evening one. Both peaks are real because both cities are employment centres.
If you have any flexibility, the midday window between 10 a.m. and 3 p.m. is genuinely fast in both directions — closer to the free-flow number than to the peak one.
Before you leave
Ten miles, two bridges, no way around a lake. When one goes down, the trip triples.
BoardSpy watches both crossings in real time and tells you before you leave which one is moving — with live wind and weather on the bridges, and an alert when today is a day the train wins.
Related BoardSpy guides
Frequently asked questions
How far is Seattle to Bellevue?
About 10 miles downtown to downtown. Free-flow is 15–20 minutes. Weekday peaks run 35–45 minutes on I-90 or SR 520. Pattern estimates, not live times.
How long is the light rail from Seattle to Bellevue?
Sound Transit’s 2 Line takes about 22 minutes in-vehicle from downtown Seattle (International District) to Downtown Bellevue, or about 25–28 minutes to Westlake. Times stay fixed because the line uses dedicated rail across I-90.
Is I-90 or SR 520 better?
From downtown Seattle to downtown Bellevue, I-90 is usually shorter. From the University District or north Seattle, SR 520 is the obvious choice. Both are floating bridges with no lake diversion if one fails.
When is the worst time to drive Seattle to Bellevue?
Westbound into Seattle 6:00–9:30 a.m. and eastbound toward Bellevue 3:00–7:00 p.m. Midday 10:00 a.m.–3:00 p.m. is the best window in both directions.
Are the Lake Washington bridges tolled?
SR 520 is tolled, with rates that vary by time of day and Good To Go. I-90 has express lanes with their own rules. For a daily commute, price the toll against Link fares.
References
Posted signs and operator timetables override this guide. Drive-time windows are pattern estimates, not measured figures for today.
- Sound Transit 2 Line — Link 2 Line schedules; the Seattle–Bellevue crossing opened 28 March 2026.
- Sound Transit 2026 service plan travel estimates — Bellevue–Seattle (International District) about 22 minutes in-vehicle.
- BoardSpy data sources — How leave-time recommendations use a saved route (limits disclosed).