Our friends over at Air Canada are having some discount deals from Delta hub cities to Tokyo-Haneda for $561 roundtrip. Fares at this price are available from Atlanta (ATL), Detroit (DTW), and Minneapolis (MSP).
Departures are available Sunday through Thursday starting in late October through the middle of December, with returns available in January 2019. A 7-night stay is required and on some itineraries, there might be a long layover or overnight required. But those can be avoided if you're flexible with travel dates.
As an example, searching on Priceline, I found tickets departing ATL on Tuesday, December 11 and returning from HND on Monday, December 24, 2018. It's best to book through a third-party site like Priceline or CheapOair as their prices are about $90 less than what the Air Canada site is offering. But if you feel more comfortable booking directly with the airline, it will cost $650 for most dates, which is still below the average price on this route.
I recommend you book these ASAP as they probably won't be around long at this price. If you're on the fence, the third-party sites I listed above will allow for free cancelations within 24-hours, so you can purchase now and cancel tomorrow in case of a change of mind.
If you aren't near any of those cities, still have a look at our Tokyo (HND) flight page, as Air Canada has other deals from U.S. airports for hundreds less.
Need a place to stay in Tokyo? We've got you covered with a long list of options provided by Hotelwatchdog.
