Passport? Good.

Japan

Arriving

The first hour — getting out of the airport and into the city.

A Narita Express train at Shibuya station

How do you get from the airport into the city?

By train, nearly always. Which train depends on the airport and on which side of the city you are sleeping.

Narita International Airport
The Keikyu line ticket gate inside Haneda Airport Terminal 1 and 2 station

Narita or Haneda — does it matter which one you land at?

By about an hour, yes. Haneda sits inside Tokyo; Narita is in the next prefecture.

Narita International Airport
A baggage delivery counter in the arrivals area at Narita Airport

Can you send your suitcase to the hotel instead of carrying it?

Yes. Counters in the arrivals hall will forward a suitcase to your hotel, usually arriving the next day.

Narita International Airport
Coin lockers at a Japanese railway station

Where can I leave my luggage for the day?

Two separate systems: coin lockers you work yourself, and staffed counters that will hold a bag for up to two weeks.

Narita International Airport — Coin-operated lockers
Oversized baggage space at the rear of a Tokaido Shinkansen car

Can I take a large suitcase on the shinkansen?

Yes, but once the three sides added together pass 160cm you have to reserve the space in advance.

JR Central — Oversized baggage

Sort the practical stuff before you fly.

eSIMs, rail passes, and airport transfers — the things worth booking before you land.