There is a recent service called Ecbo Cloak which eliminates two of the biggest unknowns regarding coin lockers in Tokyo.
You can usually check large items; and, you can also make a reservation so you don’t have to hope that there’s an opening.
It basically hooks you up with a nearby restaurant, hotel, internet cafe, etc which has committed some storage space either behind their desk, in the back room, or wherever. Kinda like Uber for coin lockers. There are locations all around the city, and likely to find one near your hotel or train station.
The easy, safe and cheap option is train station lockers, which can be found at all major train stations in Tokyo (and Japan). Japanese lockers are usually narrow but deep, so while hard plastic suitcases will not fit into them, backpacks are generally not a problem. Some larger stations (eg. Tokyo stn) also have manned left luggage counters (手荷物預かり所 nimotsu-azukari-dokoro), which can handle any size of bag and only cost a bit more than lockers. On station maps, these are usually shown with a “bag-and-key” icon, while lockers are “bag-in-box-with-key”.
Which one to recommend, though, is going to depend on what you were going to do during your day in Tokyo and how you’re planning to get around.
I probably would not recommend Tokyo station: it’s huge, remarkably confusing, not terribly close to anything interesting (although naturally it’s well connected to the entire city), and not super easy to get to from Haneda. That said, there are very cheap buses from Tokyo stn to Narita, so if you’re really pinching pennies it might be worth hassle.
One tip: when you do leave your bag, pay careful attention to where the locker is and how you got there, these are all massive stations and (voice of experience) it’s no fun running around trying to figure out where the hell you left it…
Credit:stackoverflow.com‘