SQ A350 vs. 777-300ER: Which Premium Economy Seat is Actually Better?

If you have the luxury of choosing between the Airbus A350-900 and the Boeing 777-300ER for your next Singapore Airlines flight, you might assume the experience is identical. After all, both aircraft feature the same leather-clad recliner seats and the same "Book the Cook" service.

However, frequent flyers know that the physical aircraft makes a surprising difference in how that seat actually feels. Depending on whether you prioritize personal space or cabin environment, one of these planes is a clear winner.

Here is the breakdown of the A350 vs. the 777-300ER in Premium Economy.

The Space Factor: Boeing 777-300ER Wins on Width

When it comes to raw real estate, the Boeing 777-300ER has a slight edge. Because the 777 has a wider fuselage than the A350, Singapore Airlines was able to be a bit more generous with the seat dimensions.

• 777-300ER Seat Width: 19.5 inches
• A350-900 Seat Width: 19 inches

While a half-inch sounds negligible, you can feel it during a 12-hour haul. In the A350, the 2-4-2 configuration feels a bit tighter, and the aisles are noticeably narrower. If you are someone who values shoulder room or simply wants the widest seat possible, the "Triple Seven" is your best bet.

The Environment Factor: Airbus A350 Wins on Comfort

While the Boeing offers more width, the Airbus A350 is the hands-down winner for overall well-being.

The A350 is a much newer aircraft built with carbon-fiber composites, which allows for two things that significantly reduce jet lag:

1. Lower Cabin Altitude: The plane is pressurized to a lower altitude, meaning your body absorbs more oxygen.
2. Higher Humidity: The composite frame doesn't rust, so the airline can keep the air much less "bone-dry" than on older metal planes like the 777.

Additionally, the A350 is remarkably quiet. The roar of the engines is reduced to a low hum, making it much easier to sleep or enjoy a movie without noise-canceling headphones working overtime.

The "Secret" Solo Seats: The A350-900ULR Perk

If you happen to be flying on the A350-900ULR (the Ultra-Long-Range version used for non-stop flights to New York or Los Angeles), there is a unique feature that the 777 can’t touch: Solo Window Seats.

Toward the back of the Premium Economy cabin on the ULR (specifically rows 40-42), the fuselage narrows, and the airline has placed single seats by the window with a large storage bin where the second seat would normally be. For solo travelers, these are the best seats in the sky—you get window views and direct aisle access with zero neighbors.

Cabin Intimacy

The size of the cabin also dictates the level of service and quiet you can expect:

• Standard A350-900: Features a very small, intimate cabin of just 24 seats (3 rows). This usually results in faster meal service and a more private feel.
• 777-300ER: Typically has 28 to 36 seats, making it feel a bit busier.
• A350-900ULR: This is a massive Premium Economy operation with 94 seats. It feels less like an "exclusive" cabin and more like a primary cabin because there is no standard Economy on this plane.

The Verdict: Which Should You Choose?

• Choose the Boeing 777-300ER if: You want the widest seat possible and don't mind a slightly noisier, drier cabin. It’s the "classic" choice for space.
• Choose the Airbus A350-900 if: You want to arrive feeling refreshed. The quiet engines and better air quality make a massive difference in how you feel 24 hours after landing.
• Choose the A350-900ULR if: You are traveling solo and can snag one of those rare single window seats.

Regardless of which aircraft you fly, the jump from standard Economy is a significant one. To see exactly how these seats compare to the back of the plane, check out our guide: Singapore Airlines Economy vs Premium Economy: Is the upgrade worth it?.