About Japan Flights

A price tracker that finds the cheapest flights from Tokyo (HND + NRT) plus the inverse direction USA → Tokyo, for the next 30 days. Free to use, no accounts, no tracking.

What this is

Japan Flights checks the lowest published fare across hundreds of routes covering Asia, Europe, the Americas, the Middle East, Oceania, and domestic Japan — plus a separate USA → Tokyo view for travelers heading the other way.

Five views are available: one-way, 7-day round-trip, Fri–Sun weekend, domestic Japan, and USA → Tokyo. Each price links directly to Google Flights, where the booking happens.

How it works

• Fare data is queried from Google Flights for a 30-day forward window.
• Prices are in JPY for one adult, economy cabin.
• For each destination, cheaper dates are set in bold ink over a faint red field while pricier ones recede, so the low fares stand out at a glance.
• The site is fully static — no accounts, no tracking, no cookies.

Browsing the site

• Destination search. Type a city or IATA code in the search box at the top of any page and a dropdown ranks the best matches. Selecting one opens the right region, scrolls the column or card into view, and pulses it briefly so it's easy to spot.
• List view and table view. Phones default to a card list (cheapest destination first); larger screens default to the matrix. A [List · Table] toggle lets you override either way and your choice is remembered between visits.
• Whole-cell taps. The entire price cell is tappable, not just the price chip — easier to hit on phones.
• "Copy link" buttons next to each region heading copy a deep link to that section so you can share or bookmark it.
• Region jump-to picker. The dropdown above the matrix uses native section headers so it's quick to scan on iOS and Android.
• Mistake-fare alerts banner appears at the top of each page when the detector flags drops below a route's normal noise band or a price floor. Click any alert to open Google Flights for that date.

Mistake-fare detection

On top of the matrix, a separate detector flags prices that look like genuine mispricings rather than ordinary sales. It runs every scan and surfaces alerts as a banner at the top of each page.

• Per-weekday baseline. Each route's history is bucketed by weekday. A Wednesday flash deal on a route where Tuesdays are normally cheap will show up; a normal-cheap Tuesday will not. Detection uses median + median-absolute-deviation so the threshold adapts to each route's volatility.
• Absolute-price tripwires. Conservatively curated floors per long-haul destination flag clearly-impossible fares (e.g. NRT→LAX one-way under ¥25,000) regardless of history — useful from day 1 before a baseline exists.
• Bidirectional symmetry. If the same route mispriced on both ex-Tokyo AND ex-USA passes (same metal, both directions), confidence is much higher and the alert is ranked above single-direction signals.
• Carrier & routing filter. When enabled, each alert is enriched with the cheapest itinerary's airline and stop count. Alerts whose cheapest routing has 3+ stops are dropped (real-but-useless 40-hour itineraries).

Refresh schedule

Scans run three times a day at 06:00, 14:00, and 22:00 JST. To stay a polite consumer of Google's data and avoid rate limits, not every view refreshes on every cycle:

• One-way, round-trip, weekend, and domestic Japan — refreshed every 8 hours (all three slots).
• USA → Tokyo — refreshed once a day on the 06:00 JST cycle. Long-haul transpacific fares move slowly, so daily is plenty.
• Watchlist routes (a small set of LCC-churn / mistake-fare-prone routes) are scanned every slot so short-lived fares get caught in time.

If a scan can't reach Google or returns no prices, the page keeps showing the last successful scan with a ⌛ Showing prior scan banner so you can see how stale the data is. Nothing on the site ever silently goes blank.

What this is not

This is not a booking platform and is not affiliated with Google, any airline, or any travel agency. Fares shown are a snapshot at scan time and can shift due to availability, demand, or sales between scans. Always verify the price on Google Flights before booking.