The 90-Minute Rule: Building a Layover Plan That Actually Works

Why layovers go wrong

Most layover disasters are not caused by bad luck. They come from planning the fun part first and the boring part last. Travelers decide they want to see the city, then squeeze the return trip into whatever is left. The 90-minute rule flips that order.

The rule is simple: the last 90 minutes before departure belong to the airport. Not to the train, not to a final coffee in town. That block absorbs a slow immigration line, a security re-screen, a gate at the far end of the terminal, and the normal padding an airline expects before boarding closes.

How to run the math

Start with your total layover. Then subtract in this order:

1. Arrival buffer (45–75 min). Deplaning, walking, finding your way. Add 30 minutes if you land in a different terminal from your departure.
2. Immigration and exit (20–60 min). Only if you’re leaving. Ask the airport guide for typical queue times; the early-morning bank at Haneda and evening arrivals at CDG both run long.
3. Transit, both ways (from the airport guide). Use the realistic time, not the marketing time. Add 15 minutes each way for finding platforms and buying tickets.
4. The 90-minute return buffer. Non-negotiable.

What’s left is your usable window. If it’s under two hours, the city trip is not worth the stress. Stay airside and build a good rest-eat-work plan instead.

The worked example: 8h 45m at HND

• 1h 15m — arrival buffer and terminal logistics
• 4h 30m — city window (Keikyu to Shinagawa, or monorail to Hamamatsucho)
• 1h 45m — return travel plus immigration
• 1h 15m — pre-departure meal, lounge or rest inside the 90-minute rule

Notice that the “city window” is only about half the layover. That’s normal. A plan that spends 70% of the layover in the city is a plan that assumes nothing goes wrong.

When to stay airside no matter what

• Separate tickets with checked bags that you must collect and re-check.
• A visa or ETA requirement you haven’t cleared.
• Arrival after the last train and before the first.
• Weather that is already delaying your inbound flight.
• Airports where leaving is expensive or slow (CDG’s RER at rush hour, IST’s 40 km, LHR with an ETA to organise).

Frequently asked

How long a layover do I need to leave the airport?

As a rule of thumb, six hours or more for a short city visit, and eight or more to relax. Subtract immigration, transit each way and a 90-minute return buffer before you decide.

Is a 60-minute international connection safe?

Only when the airline publishes it as a legal connection on one ticket, in a compact terminal, with no terminal change. Even then, a delay of 20 minutes puts you at risk. Prefer 90 minutes or more.

What if my flights are on separate tickets?

Treat it as two trips. Nobody will rebook you if the first flight is late. Allow three hours minimum, more if you have to collect and re-check bags.