Direct (nonstop) flights from Ontario to Seattle
3 airlines fly nonstop from Ontario International Airport (ONT) to Seattle Tacoma International (SEA). It's 956 miles (1,538 km), about 2h 54m in the air. Operated by Alaska Airlines, Delta Air Lines, Frontier Airlines.
Alaska Airlines
Delta Air Lines
Frontier Airlines
Route data last updated: May 29, 2026
Airlines with non-stop flights
AS
Alaska Airlines
DL
Delta Air Lines
F9
Frontier Airlines
Alternative Routes
Other ways to fly from Ontario to Seattle with one stop · direct emits 161 kg CO₂ per passenger
Looking for the return flight?
SEA → ONT: Flights from Seattle to OntarioOther direct flights from Ontario
Direct flights from Seattle (SEA)
Frequently Asked Questions
How long is the direct flight from Ontario to Seattle?
A nonstop flight from Ontario (ONT) to Seattle (SEA) takes approximately 2 hours and 54 minutes. The distance is 956 miles (1,538 km).
Which airlines fly nonstop from Ontario to Seattle?
3 airlines: Alaska Airlines, Delta Air Lines, Frontier Airlines.
Is there a nonstop flight from Ontario to Seattle?
Yes. 3 airlines: Alaska Airlines, Delta Air Lines, Frontier Airlines.
How far is Ontario from Seattle?
The flight distance from Ontario to Seattle is 956 miles (1,538 km), measured as the great-circle (shortest air) distance. That's roughly the same distance as New York to Miami.
What type of aircraft flies from Ontario to Seattle?
At 2h 54m, this route typically uses narrow-body or mid-range jets — Boeing 737 MAX or Airbus A320neo. Varies by airline.
What is the carbon footprint of a flight from Ontario to Seattle?
Roughly 161 kg CO2 per passenger one-way. That's about the same as driving 805 km.
Is the return flight from Seattle to Ontario also nonstop?
Yes — nonstop flights run both ways. Flight time may differ slightly due to wind patterns.
When is the cheapest time to fly from Ontario to Seattle?
Midweek flights (Tue/Wed) outside holiday peaks are usually cheapest. 3-6 weeks ahead is a good window for this route. Use "Check Prices" above to compare.
How early should I arrive at Ontario International Airport for this flight?
1.5-2 hours for domestic. Add more time during holidays or busy travel weekends.