AirHint found the following cheapest one-way flights from Seattle (SEA) to Porto (OPO) in March 2026 (see full year).
One-Way flights
| 29 Mar | Air France | ||
| 30 Mar | Air France | ||
| 31 Mar | Delta | ||
| 28 Mar | KLM | ||
| 25 Mar | Alaska Airlines | ||
| 27 Mar | Aer Lingus | ||
| 26 Mar | Alaska Airlines |
Also check the deals for return flights from Seattle to Porto in March.
Powered by
The deals are updated regularly. The prices may go up as tickets are purchased by other travellers. Only the cheapest flights are offered. Select a price to book and secure these cheap prices.
Find us on social media