Internet acess

I'am travelling to Japan - Tokyo on May 16-30, would you know how can i have internet acess during my 5days stay?

Rent a pocket wifi system. These are small devices that provide you with wifi. There are lots of companies that offer them; I use ToCoo as I've found them to be the cheapest. I've used them twice with no issues.

You can organise to pick up the pocket wifi at the airport post office (check the opening/closing times), or have it sent to meet you at your accommodation (let the accommodation know there is a package coming for you). When you need to return it, you just put it in the provided pre-paid envelope and drop it into any post box. Simple!

most hotel accommodations offer internet.

econnectjapan ( https://www.econnectjapan.com/products/wifi/ ) is another provider for pocket wifi ... I used them three times (2013,2014,2015) ... they have cheap low-bandwidth or versions, which I used the first years (and it was enough to check mails and some websites)

beside that the number of public wifi increased a lot in the last years ... you could be sure to have free wifi on air-ports ... and afaik on a lot of subway-stations ... as well as most Hotels