International Travel from Sea-Tac Airport

Yep, 3 hours should be fine.

Arrived 3 hours early in August for flights to Europe and had no problems.

I alweays fly out of SeaTac, and arrive 3 hours early for an international flight. The "S" and "N" (north and south satellite) gates are now much nicer than in days of old - so if you find yourself through security and all checked in at your gate a little earlier than you'd planned on, the wait is no longer a grim, food-and-drink-free hell. :D

Actually there have been food and drinks available in N and S gates since I began traveling from Sea-Tac in 1980. Granted it was a restaurant and a bar, not the multiple choices of fast food we have today. This is what C Gates looked like at Sea-Tac in December, 1987 (I took this photo while waiting for a red eye flight): http://hull534.smugmug.com/photos/437873215_pCGZT-XL.jpg

I arrive 2 hours before my international flight and it was always O.K. Plenty of time.

I would think 3 hours is overkill - most airport these days publish how long it takes to get through security which is probably going to be the most time consuming part of checking in (assuming carry on luggage). I would doubt you need much more than 1.5-2 hours - do some research and determine what you feel comfortable with. For me, I would never think of leaving home 4 hrs before a flight especially when I am looking at total travel time of 16+ hours to Europe and a lot more if going to Asia or the Middle East.

The ONLY international travel we have done in the last 8 years has been out of SeaTac, and we've always arrived at the airport 1.5-2 hours before scheduled departure time and found ourselves wondering what to do with all the extra time. Typically we walk through the shops, stop for a breakfast or a drink (depending on time of day), then stroll to the departure gate. It might help that we don't check baggage and we always check in via internet the day before our flight departure to (theoretically) save time in the airport. I would go crazy from boredom if I arrived at the airport 3 hours ahead of departure. 2 hours ahead for domestic flights is way too much (I suggest 1-1.5 hours) and 3 hours ahead for international flights is even more waaayyy too much - 1.5-2 should be plenty. Of course, you're flying to Amsterdam, which by definition means you are either carrying drugs or carrying tons of money with the intent to buy drugs, so you might want to budget extra time for pat-downs, strip-searches, cavity-searches, jail time, and the like.