United Flight 721 Deals & Information (2026/2027)

Wander Wisely with exceptional service, 24/7 supportOpens in a new window

Feel at ease with free flight cancellations within 24 hours of booking

Change your flight without a fee on select flights

United Flight 721 Route Deals From $82

The cheapest prices found with in the last 7 days for return flights were $119 and $82 for one-way flights to Washington Dulles Intl. for the period specified. Prices and availability are subject to change. Additional terms apply.

Tue, Apr 28 - Wed, Apr 29
BOS
Logan Intl.
IAD
Washington Dulles Intl.
$119 Roundtrip, found 6 days ago
$119
Roundtrip
found 6 days ago
Select United flight, departing Tue, Apr 28 from Logan Intl. to Washington Dulles Intl., returning Wed, Apr 29, priced at $119 found 6 days ago
Tue, May 5 - Wed, May 6
BOS
Logan Intl.
IAD
Washington Dulles Intl.
$137 Roundtrip, found 14 hours ago
$137
Roundtrip
found 14 hours ago
Select United flight, departing Tue, May 5 from Logan Intl. to Washington Dulles Intl., returning Wed, May 6, priced at $137 found 14 hours ago
Tue, May 12 - Wed, May 13
BOS
Logan Intl.
IAD
Washington Dulles Intl.
$140 Roundtrip, found 14 hours ago
$140
Roundtrip
found 14 hours ago
Select United flight, departing Tue, May 12 from Logan Intl. to Washington Dulles Intl., returning Wed, May 13, priced at $140 found 14 hours ago
Tue, May 5 - Wed, May 6
BOS
Logan Intl.
IAD
Washington Dulles Intl.
$147 Roundtrip, found 14 hours ago
$147
Roundtrip
found 14 hours ago
Select United flight, departing Tue, May 5 from Logan Intl. to Washington Dulles Intl., returning Wed, May 6, priced at $147 found 14 hours ago
Tue, May 12 - Wed, May 13
BOS
Logan Intl.
IAD
Washington Dulles Intl.
$149 Roundtrip, found 14 hours ago
$149
Roundtrip
found 14 hours ago
Select United flight, departing Tue, May 12 from Logan Intl. to Washington Dulles Intl., returning Wed, May 13, priced at $149 found 14 hours ago
Tue, May 5 - Wed, May 6
BOS
Logan Intl.
IAD
Washington Dulles Intl.
$157 Roundtrip, found 14 hours ago
$157
Roundtrip
found 14 hours ago
Select United flight, departing Tue, May 5 from Logan Intl. to Washington Dulles Intl., returning Wed, May 6, priced at $157 found 14 hours ago
Tue, May 12 - Wed, May 13
BOS
Logan Intl.
IAD
Washington Dulles Intl.
$159 Roundtrip, found 14 hours ago
$159
Roundtrip
found 14 hours ago
Select United flight, departing Tue, May 12 from Logan Intl. to Washington Dulles Intl., returning Wed, May 13, priced at $159 found 14 hours ago
Fri, May 8 - Tue, May 12
BOS
Logan Intl.
IAD
Washington Dulles Intl.
$160 Roundtrip, found 1 day ago
$160
Roundtrip
found 1 day ago
Select United flight, departing Fri, May 8 from Logan Intl. to Washington Dulles Intl., returning Tue, May 12, priced at $160 found 1 day ago
Wed, Apr 22 - Wed, Apr 29
BOS
Logan Intl.
IAD
Washington Dulles Intl.
$163 Roundtrip, found 18 hours ago
$163
Roundtrip
found 18 hours ago
Select United flight, departing Wed, Apr 22 from Logan Intl. to Washington Dulles Intl., returning Wed, Apr 29, priced at $163 found 18 hours ago
Tue, May 12 - Wed, May 13
BOS
Logan Intl.
IAD
Washington Dulles Intl.
$164 Roundtrip, found 14 hours ago
$164
Roundtrip
found 14 hours ago
Select United flight, departing Tue, May 12 from Logan Intl. to Washington Dulles Intl., returning Wed, May 13, priced at $164 found 14 hours ago
Mon, May 11 - Tue, May 12
BOS
Logan Intl.
IAD
Washington Dulles Intl.
$166 Roundtrip, found 2 days ago
$166
Roundtrip
found 2 days ago
Select United flight, departing Mon, May 11 from Logan Intl. to Washington Dulles Intl., returning Tue, May 12, priced at $166 found 2 days ago
Wed, May 20 - Mon, May 25
BOS
Logan Intl.
IAD
Washington Dulles Intl.
$167 Roundtrip, found 1 day ago
$167
Roundtrip
found 1 day ago
Select United flight, departing Wed, May 20 from Logan Intl. to Washington Dulles Intl., returning Mon, May 25, priced at $167 found 1 day ago
Tue, May 12 - Wed, May 13
BOS
Logan Intl.
IAD
Washington Dulles Intl.
$169 Roundtrip, found 14 hours ago
$169
Roundtrip
found 14 hours ago
Select United flight, departing Tue, May 12 from Logan Intl. to Washington Dulles Intl., returning Wed, May 13, priced at $169 found 14 hours ago

Frequently asked questions

What route does flight number UA721 take?
UA721 serves multiple routes, but the most common is between Sacramento, CA Airport (SMF-Sacramento Intl.) and IAH. If your flight goes direct, you'll land in around 3 hours and 37 minutes. Multi-stop flights can also use this number, as can services on other routes.
What terminal does UA721 fly out of?
If you're booked on a flight from SMF, there's a good chance you'll board the aircraft from Terminal A. The most traveled route for UA721 is SMF to Houston Airport, which is a direct flight.
What kind of plane is on flight number UA721?
There's every chance you'll be aboard a Boeing 737-800 if you've booked a fare from Sacramento Airport to George Bush Intercontinental Airport (IAH), the most popular route for flight number UA721.
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 UA721 flight with Travelocity, please visit our Customer Service Portal.