Connection time at Dulles (IAD) domestic to international

Yes if your flight lands on time. Both flights will be at the same terminal (C and D are connected). I think it is somewhat risky because there is no room for air traffic or weather delays.

That flight to Venice is a new flight and it is the only non-stop flight to Venice from IAD. I would check to see if there are later connecting flights the same day from IAD on United or Star Alliance partners just to see what might be an option if your flight arrived late. There are some late night flights (after 10pm) on both United and Lufthansa from IAD to Europe so there is a possibility that they could get you out that same day if your inbound flight were delayed.

+1 to what Laura said.

The benefit of United through IAD is the the C/D Terminal is all United. At best you'll get off the Seattle flight at one gate and walk 5 or 10 yards across to the next gate. At worst you'd walk from the far D end of the building to the far C end -- which is one long structure and end to end can be walked in 15 minutes.

I do recommend having and using United's app.

That should be enough time. IAD is not hard to get around. You are not checking a bag. I would not worry about it. make sure that you go directly to the gate when your flight lands. I would also resent my PP at the Seattle airport when you get your boarding passes.

Thank you all for responding. I think it will be alright. If UA changes the flight again and if it's less than an hour connection, I will worry. Happy to know the gates are fairly close together. I now have the United airlines app

A couple of years ago we flew United from San Francisco to Dulles with a 60 minute layover to Paris, no problem. The United App should tell you your gates.