JCI offers under the b-mobile brand a number of low-speed data SIMs. The advertised speed of these SIM cards range from 150 to 400 kbps, and there are no monthly limits on data usage. While these SIMs are very inexpensive and great for what they are advertised (short communications and light maps usage), traffic is heavily shaped, often resulting in high latency that adversely affects usability.
Turbo Charge can be toggled on and off by an android app (requires a mobile data connection to make the switch - you cannot toggle it via wifi). Turbo charges are pre-purchased and valid for 180 days. B-mobile subtracts data by the byte.
- ¥525: 100MB valid over 180 days (¥5.25/MB)
- ¥1,800: 500MB valid over 180 days (¥3.6/MB)
Users of this report very favorably. For someone who typically doesn't need a lot out of a mobile data connection, the least expensive voice plan in the Aeon or smartphone voice SIM, with the 150 kbps data plan, coupled with a few turbo boost purchases each year, would provide by far the most economical option for a smarphone plan.