United Flight WN400 Deals & Information (2024/2025)

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United Flight 400 Route Deals From $99

The cheapest prices found with in the last 7 days for return flights were $209 and $99 for one-way flights to Washington Dulles Intl. for the period specified. Prices and availability are subject to change. Additional terms apply.

Tue, Jun 18 - Sat, Jun 29
DEN
Denver Intl.
IAD
Washington Dulles Intl.
$209 Roundtrip, found 7 hours ago
$209
Roundtrip
found 7 hours ago
Select United flight, departing Tue, Jun 18 from Denver Intl. to Washington Dulles Intl., returning Sat, Jun 29, priced at $209 found 7 hours ago
Thu, May 30 - Sat, Jun 1
DEN
Denver Intl.
IAD
Washington Dulles Intl.
$217 Roundtrip, found 1 day ago
$217
Roundtrip
found 1 day ago
Select United flight, departing Thu, May 30 from Denver Intl. to Washington Dulles Intl., returning Sat, Jun 1, priced at $217 found 1 day ago
Sat, Jun 8 - Tue, Jun 11
DEN
Denver Intl.
IAD
Washington Dulles Intl.
$230 Roundtrip, found 5 days ago
$230
Roundtrip
found 5 days ago
Select United flight, departing Sat, Jun 8 from Denver Intl. to Washington Dulles Intl., returning Tue, Jun 11, priced at $230 found 5 days ago
Thu, Jul 25 - Mon, Jul 29
DEN
Denver Intl.
IAD
Washington Dulles Intl.
$237 Roundtrip, found 1 day ago
$237
Roundtrip
found 1 day ago
Select United flight, departing Thu, Jul 25 from Denver Intl. to Washington Dulles Intl., returning Mon, Jul 29, priced at $237 found 1 day ago
Tue, Jun 18 - Sat, Jun 29
DEN
Denver Intl.
IAD
Washington Dulles Intl.
$239 Roundtrip, found 7 hours ago
$239
Roundtrip
found 7 hours ago
Select United flight, departing Tue, Jun 18 from Denver Intl. to Washington Dulles Intl., returning Sat, Jun 29, priced at $239 found 7 hours ago
Thu, Jul 11 - Sat, Jul 13
DEN
Denver Intl.
IAD
Washington Dulles Intl.
$244 Roundtrip, found 2 days ago
$244
Roundtrip
found 2 days ago
Select United flight, departing Thu, Jul 11 from Denver Intl. to Washington Dulles Intl., returning Sat, Jul 13, priced at $244 found 2 days ago
Thu, Aug 8 - Mon, Aug 19
DEN
Denver Intl.
IAD
Washington Dulles Intl.
$249 Roundtrip, found 1 day ago
$249
Roundtrip
found 1 day ago
Select United flight, departing Thu, Aug 8 from Denver Intl. to Washington Dulles Intl., returning Mon, Aug 19, priced at $249 found 1 day ago
Tue, Jun 18 - Sat, Jun 29
DEN
Denver Intl.
IAD
Washington Dulles Intl.
$250 Roundtrip, found 7 hours ago
$250
Roundtrip
found 7 hours ago
Select United flight, departing Tue, Jun 18 from Denver Intl. to Washington Dulles Intl., returning Sat, Jun 29, priced at $250 found 7 hours ago
Thu, Aug 8 - Mon, Aug 19
DEN
Denver Intl.
IAD
Washington Dulles Intl.
$252 Roundtrip, found 1 day ago
$252
Roundtrip
found 1 day ago
Select United flight, departing Thu, Aug 8 from Denver Intl. to Washington Dulles Intl., returning Mon, Aug 19, priced at $252 found 1 day ago

Frequently asked questions

What route does flight number UA400 take?
UA400 operates from Dulles Intl. Airport to Raleigh–Durham Airport and is a direct flight. This trip takes 1 hour and 11 minutes.
What kind of plane is on flight number UA400?
The route for flight number UA400 is generally Dulles Intl. Airport to RDU, and the Boeing 737-800 is the aircraft model you’ll probably be flying with.
If I am not able to travel due to COVID-19, can I change my flight to a later date?
For more info about changing your UA400 flight with Travelocity, please visit our Customer Service Portal.