Data only, no calls. You need to view ads and complete a survey to get this for free.
Good insurance policy as it gives access to Google Maps/WhatsApp in case a group member gets separated from the group.
Further details can be found on the Prepaid Data SIM Wikia: www.prepaid-data-sim-card.wikia.com/wiki/Japan#Japan_Welcome…
You can pick up these SIMs for free here at various airports, however you must register online in advance.
Data speeds limited to 128kb/s. SIM valid for 15 days.
Tell me how it goes :)
I've used Docomo sim cards, usually there are data limits per day for sim cards in japan. They are usually 3g or 4g speeds for around 500mb each day depending on what plan you paid for. After you use up your data allowance for the day, they will automatically reduce you down to 128kbps speeds for the rest of that day. Running at these speeds basically gets you nothing, its just too slow to do anything. Unless you are planning on not purchasing a data plan such as a sim card or a pocket wifi. Maybe this is better than nothing.