It’s not a myth that Tokyo hotel rooms tend to be small. This is because most of the more economical hotels were originally built to service Japanese business people who only needed somewhere to rest for a night or two while travelling for work. They weren’t built for foreign tourists more used to a bit more space.
Be sure to check the square meterage of hotel rooms via the hotel or travel website you use before booking to ensure you are comfortable. As a general rule, many of the mid-range and lower priced hotels tend to have small rooms. It’s the more expensive hotels and international chains that tend to have room sizes more common in the West. If you’re travelling solo, a room around 18m square is perfectly comfortable, without being roomy. But selecting a room that size or smaller for a couple will see you climbing over each to move around and struggling to find floor space to open your suitcases.