Taxis in Japan are generally the same as everywhere else in the world. Depending on the type you get (van or car), you can rest easy knowing that your luggage will fit into the vehicle and have room to spare. For shuttles, it might depend on the service, but generally they allow two pieces of luggage per person.

Public buses are frequently used by the Japanese populace. Depending on the area of Japan you are in, some buses might become really crowded, so traveling with a lot of luggage can be an issue for some. Public buses will not have a designated area to store luggage, therefore you have to keep it with you at all times. Private buses however, will allow up to two pieces of luggage per person, as well as a carry on.

Local airplanes follow the same rules as international flights in regards to luggage. Depending on your carrier, you will be allowed one to two pieces of luggage and one carry-on item.

City and public trains have an overhead storage area above the seats that can hold small to medium sized luggage. Big items will have to stay on the floor near your person. Shinkansen and private trains will usually have a designated area near the entry doors where you can stack your luggage. If that is not available, there is usually an empty space at the end of each car where you can store your luggage.

Make sure to let the conductor know, as unattended luggage may be confiscated for security reasons. If you have a backpack, it is generally suggested that you store it in the overhead storage or to carry it in your hands in order to avoid disturbing people behind you.

If traveling with a lot of luggage seems to be more hassle than what it's worth, it would be best to look into the delivery services in a variety of major airports, train stations, convenience stores, and even participating shops.

- Airports
You can find a delivery counter in all major, and some minor airports in Japan. Tourists can drop off luggage at the counter and have it delivered to their hotel. There are various companies that offer this service and charges may run anywhere from 1,000 to 4,000 yen, depending on the size of the luggage and where it will be delivered.

- Hotels
Many hotels have a cloak service that will hold your luggage while you wait for the check-in time. Major hotels offer a delivery service and will be happy to transfer your luggage from one hotel to another. It is important to note however, that it is best to inform the hotel receiving your luggage about the delivery to help avoid any complications. Prices may vary from hotel to hotel, as for the size of the luggage, and finally for regular or express delivery.

- Convenience Stores
Convenience stores can be found just about anywhere in Japan and they are also a great way to send your luggage to a hotel, private residence, an airport, and more!

- Souvenir Shops
Many souvenir shops across Japan have an option to deliver your recently bought goods to an address of your choosing. Depending on the shop, international shipping may be available as well. Fees and costs vary depending on the shop.