Ryokan are traditional Japanese inns, and they are different from Western-style hotels. Guest rooms in ryokan are Japanese-style and are covered by tatami mats. In general, people don't wear shoes inside ryokan and walk around in slippers. If slippers are provided at the entrance, please take off your shoes and change into the slippers. After guests check in, usually an inn worker leads them to the guest room.
In the guest room, it's not appropriate to wear slippers on the tatami floor. Typically, a low table and za-buton cushions are set on tatami floor. A set of Japanese teapot and teacups is often prepared on the table in the guest room. Inn workers might serve tea for you in the room upon arrival.
Ryokan provide their guests with yukata (thin kimono) as room/nightwares. To relax, change to yukata if you would like. If a kimono jacket called tanzen is provided, put it on top of yukata. You can go out of your room or inns wearing yukata unless you are told not to do so. Many people change to yukata after taking a bath in the inn. Ryokan usually offer large bath facilities for guests to relax.
It's common for guests to sleep on futon spread on the tatami floor. Inn workers usually prepare futon at night and put them away into the closet in the morning. In budget Japanese inns, you might need to do it yourself.
Dinner and breakfast might be served in the guest room or in the dining room. They are usually Japanese-style meals which include rice dishes.
Even Western-style hotels offer some Japanese-style guest rooms. Please contact each hotel to find out if Japanese-style rooms are available. To find ryokan in Japan, please refer to Japanese Inn Group Website.