Sit on the Left side of the plane for the best views on flights from Seattle to Barcelona. Left side wins at both ends of the flight. At departure you get Mount Rainier and the Seattle skyline; at arrival you get the Barcelona city grid and the Pyrenees. Over the mid-Atlantic and Canadian Arctic the views are largely ocean and ice regardless of side, so the bookend scenery is the deciding factor.

During takeoff from Seattle Tacoma International (SEA), sit on the Left side for the best views. SEA typically departs north on runway 16R/34L or south on 16L/34R. Northbound departures on 34L/34R swing left over Puget Sound, giving left-side passengers a clear view of Elliott Bay, downtown Seattle, and Mount Rainier to the southeast. Right-side passengers face west toward the Olympic Peninsula with less dramatic urban framing. Notable sights include: Mount Rainier (southeast, dominant snow-capped cone), Elliott Bay and downtown Seattle skyline, Puget Sound waterway, Lake Washington to the east.

When landing at Barcelona (BCN), sit on the Left side for the best views. Barcelona's El Prat airport typically lands on runway 25L/25R or 07L/07R. Approaches from the northeast on runway 25 bring aircraft over the Mediterranean coast, and left-side seats face north toward the city — offering views of the Barcelona urban grid, the Sagrada Familia district, and the Pyrenees mountains on the horizon. Right-side seats look south over the delta of the Ebro and open sea. Notable sights include: Barcelona urban grid and coastline, Montjuïc hill, Llobregat River delta, Pyrenees mountain range on the northern horizon.

The flight from Seattle Tacoma International (SEA) to Barcelona (BCN) takes Approximately 10 to 11 hours (nonstop routing via polar/North Atlantic track, roughly 5,500 miles).

The flight typically tracks northeast from Seattle over British Columbia and Alberta, crossing the Canadian Rockies, then arcing over Hudson Bay or Labrador, crossing the North Atlantic near Greenland or Iceland depending on jet stream routing, passing over the UK or Ireland, then descending across France toward the Pyrenees and the Spanish Mediterranean coast. Notable features include the Canadian Rockies, Greenland ice sheet, and the Bay of Biscay.