MVNos like Ting Wireless, Visible, Google Fi, Mint Mobile in the US and LINE MO, Y! Mobile, and povo in Japan are “mobile virtual network operators”.

Unlike their MNO “mobile network operator” counterparts, MVNOs are generally less expensive, have different features, cater to specific markets, etc. For example, Mobal is a SoftBank and docomo MVNO that caters to foreigners, and cannot be used outside of Japan.

The biggest disadvantage to MVNOs is generally that they take the lowest priority out of all line types on a given phone plan. Data prioritization on mobile carriers usually looks something like this:

1. The MNO's highest tier of plan
2. The MNO's middle tier of plan
3. The MNO's budget tier of plan
4. The MNO's hotspot plan / tethering data (can sometimes be higher and/or on the priority of the plan above)
5. The MNO's de-prioritized customers (when customers have hit their data caps)
6. The MVNOs that are on the MNO's network

Data prioritization is different from speed caps and is closer to a quality-of-service system. In essence, if you're on an MVNO, you usually pay for it by having the lowest priority data. You might still be able to get fast data depending on the congestion level of the network at the particular location and time-of-day, but the users at the top have priority.