Once you arrive in Japan and begin work, this type of visa is valid from 6 months to one year depending on the type you have. If you are fortunate enough to have been hired overseas, your employer usually sponsors you and gets the proper visa arranged for you before you come over. This is getting increasingly risky for several reasons and cannot be recommended. Things are very expensive here. Living in the country is much cheaper than in the larger centers.
Japan is a very crowded country which makes for crowded sports facilities.
It is very difficult and expensive to get onto a golf course or tennis court for example. There is ample opportunity to join in all kinds of activities at the community level. Junior high school gymnasiums are often opened for use by the public after school hours. Each community varies so it is good to ask your students or managers at your school for information in this regard. The quick answer is, as much as you can.