Roundtrip Ontario CA to Seattle Nonstop Airfares on Delta Air Lines

No special codes or coupons are required. Get these roundtrip airfares while they are available. These are basic economy fares that allow a personal item and a carry-on bag, but no seat selection or changes are permitted.

Travel Availability

• Departs ONT: January 6-11, 13-14, 17, 20-24, 27-31; February 1-6, 11, 14, 19-20, 24, 26-28; March 2-4, 7
• Departs SEA: January 6-14, 17-18, 20-22, 24-29, 31; February 1-5, 8-10, 18, 21, 23-25, 28; March 2-3, 7, 9-10, 11

Important Exclusions

• Deal expires March 31, 2026.