Along with a restaurant, there's a coffee shop/cafe on site. You can enjoy a drink at the bar/lounge. There's an onsite 24-hour business centre.
WiFi is free in public spaces. The business-friendly Courtyard by Marriott Seattle SeaTac Airport also features a 24-hour fitness centre, laundry facilities, and dry cleaning/laundry services. A roundtrip airport shuttle is free (available 24 hours). For a fee, parking is available.
This 4-star SeaTac hotel is smoke free.