The flight distance from Seattle-Tacoma International Airport (SEA) in Seattle, United States to Sines Airport (SIE) in Sines Airport, Portugal is 8,461 kilometers (5,257 miles / 4,569 nautical miles). The estimated flight time for this route is approximately 11h, flying northeast at a heading of 48°.

This is a long-haul route typically operated by wide-body aircraft such as the Boeing 777 or Airbus A350. Full meal service, in-flight entertainment, and comfort amenities are standard.

This is an international route connecting United States with Portugal. It is an intercontinental flight between North America and Europe. Travelers should check visa requirements, customs regulations, and any travel advisories before booking.

Time zone information: When it's 02:49 in Seattle, it's 10:49 in Sines Airport. With a 8-hour time difference, travelers should plan for significant jet lag. It typically takes one day per hour of time difference to fully adjust.

The return flight from Sines Airport (SIE) to Seattle (SEA) follows a heading of 320° (northwest). Actual flight times may vary depending on wind conditions, air traffic, and the specific aircraft used.

For more information about these airports, visit the Seattle-Tacoma International Airport (SEA) and Sines Airport (SIE) detail pages, or use our flight duration calculator to compare other routes.