Hong Kong (HKG) to Ulaanbaatar (UBN): 1,794 miles (2,887 km) great-circle, about 4h 05m nonstop by our estimate. Cheapest fare observed: $488 round-trip on Air China, with 1 stop, departing May 1, 2026.
$488 round-trip, Air China CA116, departing 2026-05-01 at 20:15, returning 2026-05-03. The recorded itinerary left on a Friday, returning on a Sunday 2 nights later; the fare was observed 6 days before departure. "Book this flight" opens Kiwi.com with the same airline and dates.
At $488, it ranked 20th of the 30 round-trip fares we recorded from HKG (median $303). That is 27.2 cents per great-circle mile (round-trip price over one-way distance), above the HKG median of 22.1 cents across 30 round-trip routes.
Routes from HKG of similar length: Vladivostok (1,792 mi) at $584 and Tokyo (1,804 mi) at $232.
Air China had the cheapest fare on 6 of 30 HKG routes. It is the 12th longest of the 30 routes we track from HKG.
Of 6 departure airports with a fare to Ulaanbaatar, Hong Kong (HKG) ranked 2nd at $488. Lowest: $359 from Seoul (ICN); highest: $1531 from San Francisco (SFO); 2 nonstop. Cheapest-fare airlines (routes): Jeju Air (2), MIAT Mongolian Airlines (2), Air China (1) and Asiana (1).
Travelpayouts fares (cheapest per route, observed April 25, 2026); OurAirports coordinates and elevations; IANA zones Asia/Hong_Kong, Asia/Ulaanbaatar; flight time is our estimate.