United Flight UA3921 Deals & Information (2025/2026)

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United Flight 3921 Route Deals From $762

The cheapest prices found with in the last 7 days for return flights were $754 and $762 for one-way flights to San Francisco Intl. for the period specified. Prices and availability are subject to change. Additional terms apply.

Tue, Oct 21 - Mon, Nov 17
HKG
Hong Kong Intl.
SFO
San Francisco Intl.
$754 Roundtrip, found 2 days ago
$754
Roundtrip
found 2 days ago
Select United flight, departing Tue, Oct 21 from Hong Kong Intl. to San Francisco Intl., returning Mon, Nov 17, priced at $754 found 2 days ago
Tue, Oct 21 - Mon, Nov 17
HKG
Hong Kong Intl.
SFO
San Francisco Intl.
$759 Roundtrip, found 2 days ago
$759
Roundtrip
found 2 days ago
Select United flight, departing Tue, Oct 21 from Hong Kong Intl. to San Francisco Intl., returning Mon, Nov 17, priced at $759 found 2 days ago
Tue, Oct 21 - Mon, Nov 17
HKG
Hong Kong Intl.
SFO
San Francisco Intl.
$764 Roundtrip, found 2 days ago
$764
Roundtrip
found 2 days ago
Select United flight, departing Tue, Oct 21 from Hong Kong Intl. to San Francisco Intl., returning Mon, Nov 17, priced at $764 found 2 days ago

Frequently asked questions

What route does flight number UA3921 take?
UA3921 serves multiple routes, but the most common is between Washington, DC Airport (IAD-Washington Dulles Intl.) and BGR. If you're lucky enough to score a direct flight, you'll stroll through arrivals in 1 hour and 56 minutes. Multi-stop flights can also use this number, as can services on other routes.
What kind of plane is on flight number UA3921?
You're likely to travel aboard a Bombardier CRJ if you've reserved a ticket on flight UA3921 from Washington, DC Airport (IAD-Washington Dulles Intl.) to Bangor, ME Airport (BGR-Bangor Intl.). This is the most commonly used aircraft on this busy route.
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 UA3921 flight with Travelocity, please visit our Customer Service Portal.