Is it ever cheaper to wait until the very last day?

No. Airlines rarely drop prices in the final 48 hours for international routes. The cheapest 'last-minute' window is usually 14 to 21 days before departure.

Does using Incognito mode actually help?

It's a myth. Flight prices fluctuate based on demand and airline inventory algorithms, not your individual search history.

Booking last-minute flights to Japan without overspending

To secure affordable last-minute flights to Japan, use Google Flights' 'Track Prices' feature for alerts and prioritize flying into secondary airports like Osaka (KIX) instead of Tokyo (NRT/HND). Book at least 14 days out if possible, and be flexible with your departure city to catch regional airline deals.

Set up price tracking immediately. Go to Google Flights, input your origin and your target Japanese airport. Toggle 'Track prices' on. You will get an email the moment the price drops. Do this for multiple origin cities if you have access to more than one airport.
Use the 'Explore' map feature. Clear your destination and set it to 'Japan'. Look at the map view to see which Japanese city is cheapest to fly into for your dates. Often, flying into Osaka (KIX) or Fukuoka (FUK) can save you $200-$400 compared to Tokyo.
Check budget carriers for the final leg. If a flight to Tokyo is too expensive, look for a cheaper flight to a major Asian hub like Taipei (TPE), Seoul (ICN), or Hong Kong (HKG). From there, book a separate low-cost carrier ticket (like Peach or Jetstar Japan) into Japan.
Monitor '24-hour' rules. If you find a price that seems 'okay' but you're unsure, check the airline's cancellation policy. Many US-based carriers allow you to cancel for a full refund within 24 hours of booking, giving you a day to finalize your plans without losing the fare.

Is it ever cheaper to wait until the very last day?: No. Airlines rarely drop prices in the final 48 hours for international routes. The cheapest 'last-minute' window is usually 14 to 21 days before departure.
Does using Incognito mode actually help?: It's a myth. Flight prices fluctuate based on demand and airline inventory algorithms, not your individual search history.